Also, it is hard to see how or why neopagans would predominantly become associated with reactionary causes, Of course there is some overlap OTL But in my personal experience a neopagan, or even a "folk Christian" which I think I have also encountered, is much more likely to have a left-wing hippie sort of vibe about them, insofar as they take politics seriously at all.
Now if Aleister Crowley or L Ron Hubbard were the major template for neopaganism as practices, or "neopagans" were identical to the kind of people called witches in movies like "Rosemary's Baby," then yeah I suppose they might be quite reactionary. Certainly the Nazis OTL dabbled in all sorts of New Agey stuff which might suggest that New Age was inherently reactionary somehow. But again my personal experience with the New Age scene in the 1980s and '90s suggests no connection or common interest with right-wing American political causes of those decades.
I suppose I am fishing here for what your definition of "neo-pagan" might be, and how you'd get a continuum with conservative Christianity, which would perhaps explain how you see a linkage between this and "conservative" politics which I've been calling "reactionary." I have chosen to use the latter term, which I note is line with your scenario in that you suggest all this is a reaction to what a liberal or radical would describe as "social progress," because I don't think what we call "conservative" in the modern US political spectrum generally corresponds to a simple desire to cling to things as they have been in living memory as a superior state to the sort of society we are progressing toward; rather people who are for some reason or other upset by some of these trends create a myth of an imaginary Arcadia in the past that historically did not exist and extoll this made-up past in order to denounce and oppose what they dislike today, and as a model of the goal they seek to "re"construct. True conservatism, as expressed by say Burke in his polemic against the French Revolutionaries, requires that the old system one defends is present now, and change one hates is recent. Americans have been living at a pretty fast rate of change and generally welcomed, or even fostered, the recent changes and so there isn't much to "conserve" in any generation.
Christian fundamentalists in the USA have generally not been defenders of some bastion of old ways that they inherited and seek to protect; rather more often than not, they have been people who recognize that to implement and live the radical message of the Gospels their ways have to change. The various waves of Christian revival we experienced in the 18th and 19th centuries--Methodists, Baptists, camp meeting revivalism, etc, have generally been associated with political progressivism as much as any sort of wave of reaction. The sword cuts both ways. The trajectory of such movements has generally been that the actual time of revivalism is seen as a threat to the established order, and causes one would associate with reaction such as reinforcing the racial hierarchy have in fact been threatened in the early years of enthusiasm. Wesleyites and Baptists in their early days were known for free association of whites and blacks, for instance. Then, over time, the cult becomes "respectable" to the degree that they drop their more radical importunities and get with the mainstream program; thus these radical denominations would back off, holding up racial equality as a vague ideal for the kingdom of Heaven where it was safe to do so and finding Biblical justification for race hierarchy where that was necessary to fit in.
So, would there be a lot of people who were conservative Christians from generations back, but also clung to 'folk' traditions that you seem to imply are actually pagan in origin? I'm not sure what you mean by that--traditional medicines? Yuletide holly and ivy? If anything that seems to describe more moderate, casual traditional Christian practices. Fundies who take the Bible very seriously would tend to frown on such things rather than cling to them. The only people who have ever seriously conducted a War on Christmas were---Christians! Specifically I'm thinking of Scottish Calvinists here, who banned traditional Yuletide celebrations because they thought they were suspiciously pagan (if not Popish). (In its place a whole new holiday tradition rose in Scotland, Hogmanay).
The closest thing to what you seem to be wanting to get at would be the fundamentalism of the South, as in the Scopes trial against teaching Darwinism in the 1920s, where William Jennings Bryan came to assist the prosecution and Clarence Darrow stood for the defense. But the political values of these people cut both ways for the most part.
The modern Christian Right strikes me as being half "astroturf." I don't doubt a widespread grassroots base exists, but I do doubt that this base controls the agenda. Rather, we have here a conjunction of the power of upper class people who may or may not participate in the base churches, but do support them financially whether they believe or not, in favor of a more corporate-compliant civil order. They seek to disrupt or challenge public social services by pointing to private charities that don't need to follow public rules about fair treatment of all. They seek to discourage labor solidarity by fostering a mythos of individual accomplishment and inattention to systematic social mechanisms that limit the prospects of entire classes. But these upper class patrons are not the grassroots; those are formed from discontented and disconnected poorer people, many of whom might be suffering resentments that can be channeled to blame modernity and specific manifestations of it as the work of the Devil or human corruption, and thus be mobilized to fight battles for causes that don't address their own concrete circumstances.
Now, would it make any sense for such an "astroturf" movement to form that uses either radical neo-heathenism or some impure mix of hard-shell fundamentalist religion blended with wacky old pagan practices? I can see a place for one or the other, but how would the USA evolve in that direction?
The Nazis are quite infamous for their members dabbling in all sorts of New Agey stuff--in Wotanism, in Crowleyian Magick, in beliefs about the Tibetans that took some seekers there (along, apparently, with Soviet citizens and the US liberal/progressive Henry Wallace). Anything apparently but appealing to Christian values. By Hitler's race logic, Christianity was an offspring of Judaism, therefore tainted through and through by values deadly to the Aryan spirit. However the Nazis did not seek to systematically extirpate Christianity as such from Germany the way the Bolsheviks (in waves, between more tolerant periods) sought to dethrone Orthodoxy (and any rival cults) in the USSR. They did seek to control what the Christian hierarchy said and did, and punished excessive deviance from the Nazi line. But whenever possible the Nazis were happy to coopt Christians rather than suppress them.
What was going on there, I suppose, was the general weakening of Christianity as something to take seriously in Europe that led the Bolsheviks to believe the moment to put an end to it was at hand in Russia. Traditional people would continue to be moved by Christian appeals, but there wasn't sufficient passion left to sustain a powerful movement on Christian grounds. So Hitler could afford to cut himself loose, and then his followers to scramble around looking for some alternate spiritual base as they saw fit, which left them free to gin some up that fit more closely with the Nazi doctrines of power as an end in itself, struggle, and all that jazz.
So I suppose a neo-pagan reactionary movement might get somewhere in a USA where Christianity as such was generally discredited and ignored. Note I've been using the general catch-all of "New Age," because I don't see any reason to suppose that American reactionaries would hit upon "Heathenist" (whatever you mean by that, care for a definition?) or "Celtic Reconstructionist Pagan" as a template, much less "folk Christianity." No, they'd be more likely to go for something more novel, or even for hard-core militant atheism, I'd think. In fact they'd possibly wind up like the Nazis, where the spiritual/metaphysical underpinning can be any brew you like as long as it is not inconsistent with Nazi principles of rule and will to power (or arbitrarily ruled to be such).
How does "folk Christianity," the way you imply it work, come into play at all? Well, that's exactly what radical Protestants accuse the Roman Catholic Church of being--an ungodly amalgam of disconnected and out of context Christian phrases with pagan practices and whims decreed by Popes, a demonic parody of true Christendom. So I guess a society with a powerful "folk Christian" movement is a way of saying that a powerful Christian cult that Protestants would deem to be impure and burdened down with all sorts of rococo bric-a-brac with no Biblical source or justification attracts a strong reactionary following. If the Born-Again movement had led to conservative fundamentalists flocking to the Roman Catholic Church in droves, and these types, deeply devoted to their new-found practices of praying the Rosary and the Stations of the Cross and a bunch more stuff my own Catholic upbringing didn't even bother to explain to me (the Sacred Hearts of Jesus and Mary for instance) drove out all the liberal Catholics or silenced them and turned this Church, consolidating most of the right-wing Christians in its incense-scented aisles, toward political reaction unambiguously, decreeing once again that "liberalism is a sin," I suppose that would be a realization of your vision. But there would be no place for neo-pagan fellow travelers! In the Church--or out!
I can think of some other typical American branches of Christianity that might take the place of Catholicism and look pretty much the same to an outsider; I might argue that while Catholicism's "folk pagan" Baroque touches were acquired authentically over a couple thousand years, newer cults are making it all up on the spot. But if it works psychologically, it hardly matters, does it? Robert Heinlein's 1940 story "If This Goes On..." with its Church of Nehemiah Scudder is clearly a conception of this type.
--------
But neopaganism, as i have encountered it in OTL, while it might well lend itself to white supremacists and Neo-Nazis here and there, had not generally appeared as a refuge for disgruntled but conservative seekers dislodged from their comfort zones by liberal modernity. No, the impression one gets far more is people who want something that is if anything in advance of what contemporary modernity offers.
It may be that if I understood the grass-roots origins of say "Celtic Reconstructionist Pagans" I might shudder. All I know is, their emulators in the USA have utterly failed to attract the support of corporate sugar daddies nor have they generally been attractive to people who want to hide their racist agenda under a respectable cloak. For that, "Christian Academies" suddenly became far more popular than they had been when public school desegregation began being seriously enforced in the 60s and 70s.
If the USA had, over the course of the 19th and 20th centuries, become gradually secular in the sense of people rarely going to any church, and gradually atheistic in the sense of a majority of people proclaiming they did not believe in any religion, then perhaps the sort of white panic that swelled the enrollment in conservative Christian schools OTL might instead lead to a sudden rise in claims of religiousity of some kind or other, to cover the withdrawal of children from public schools. If atheism were the norm in 1960, these new religions might be non-Christian--but why would there not instead be a revival of traditional Christianity (in a new form reflecting the modern concerns of people seeking shelter from aspects of modernity)? Surely if people want to manufacture a fake past Utopia to get back to, they would do better to turn to a reasonable facsimile of their actual past, as historical memory would have it? A reactionary panic in an atheist mid-20th century USA would probably hark back to the staunch Christianity of the Founder generation of Patriots. (In this they'd be wrong to an extent, considering the mild Deism of so many of them, but among the Revolutionary generation and the Framers of the Constitution one can find sufficient examples of serious and devout religious observance to put a cloak of a religious consensus over the whole lot, if one doesn't look at the counterevidence too closely).
For those harking back to devout Catholicism, you might find plenty of "folk Christian" elements to gratify yourself I suppose. And despite the historic antipathy between Catholic and Protestant, I daresay that neo-Puritans and neo-Tridentines will have enough common ground in civil politics and society that they will waive the doctrinal wars (perhaps to another generation that might take it all more seriously) in favor of their joint political alliance against social modernism.
But the sort of neopaganism i found ready to hand when I was a kid and young adult in the 70s and 80s would hardly serve a conservative purpose. What attracted my pubescent eye was of course the spectacle of naked women, either allegedly running around ritual fires summoning Baphomet or whoever, or stripped under the prurient eyes of dour Inquisitors. Once I tried to raise my own prurient gaze to a higher level, I perceived the revisionist pro-witchcraft tolerance of modern times as a form of feminism.
I frankly disbelieve that much of the "reconstructed" paganism one finds nowadays, since mid-20th century eccentric Britons sought to trace a lineage between medieval and early modern "folk" practices back to Druidism, has much to do with what ancient Druidists actually believed and practiced. The emotional appeal lay mainly, I think, with female empowerment, setting wise women against the follies of patriarchy. Male gaze gawkers like myself would be part of the movement but the main drive of it clearly has been women appealing to women.
That's feminism. It might be a goofy, soft, unscientific sort of it but that's the appeal, I believe. Whereas your reactionary Americans would include feminism in any form as one of their grievances against modernity. The patriarchy of a hard form of Christianity would be far more appealing to them.
So if instead we somehow have a pagan revival for these people, it would be pretty distantly related if at all to the sort of neo-paganism we commonly see today. Nazi style Wotanism might fit. But why bypass a rich heritage of Christian bigotry, intolerance, and absolutism to revive a primitive cult that lost out to the Christians in the first place?
Neo-conservatives most of all want to associate with winners, not martyrs. The Vikings might look more manly and stark compared to martyr-ridden Christians--but the Christians of the Modern period were triumphant.
Perhaps my negativity has shown paths to what you are looking to explore that I simply refuse to go down myself. I just don't see it, not anyway in the inclusive package you offer. Some of those elements, perhaps, certainly not all of them together.
And the probable thing is OTL, a revival of old-time Christian religion, not a New Age.