It's important not to conflate ecomomic & welfare policy with civil rights in assessing just what a surviving JFK might do.
Personally I don't see why JFK can't get the same Medicare, Medicaid and war on poverty legislation through as LBJ did. If need be he'll just have to wait until after a decisive reelection victory against Goldwater (LBJ was able to get the war on poverty going in the months after the assassination).
Civil rights is another matter altogether.
As I have posted in the Kennedyarchy deal, enough Senators had pledged support pre-JFK assassination that the bill was likely to pass regardless.
I think RFK gets the nomination if he makes a serious run in 1968. But he wouldn't get it because he was, like, totally awesome--no, he would be the winner as he has the White House and the party elite behind him, as (broadly speaking) Stevenson had in '52, Nixon in '60, and HHH did in OT's '68. Though the big problem for him is that the sitting president can't be as aloof from the nominating process as the POTUSES in those other cases were.
I think LBJ will be pretty rundown in this scenario, very demoralised. He's had his medical problems. I can't see him fighting his first hard electoral battle in twenty years as an old man.
Though there is one man he can put forward who can put a hurt on young Bobby--Governor John Connally.
I really have a problem with the idea of Bobby in 1968 in a JFK lives scenario (perhaps tipping my hat a bit for my own timeline), no matter how many times I may have seen it. I have yet to be convinced it'd work. Unless he had left the AG post and sought office by 1964 or so, I just can't see it, because he'd seriously lack experience.
I can see LBJ run, especially if he sees a chance Bobby would run (he hated him since he tried to keep him off the 1960 ticket), and if he thought he was Kennedy's true successor. But, as I said before, I don't think he'll get the nomination. But I don't see him as demoralized. He'd not have to go through 4 or so years of "Hey, Hey, LBJ, How many kids did you kill today?" nor the stressors he went through besides that. I'm also speaking beyond this scenario as I have issue with it, as I said previously. He could also live some years past 1973 because of that lack of stress, as a matter of fact.
Now, who'd be the Democratic nominee in 1968, I don't know. Could it be Humprey, a favored Democrat with ample experience; perhaps? Could it be Terry Sanford, a politician Kennedy liked and viewed as being in line with his views and perhaps even his most proper successor; perhaps, although the Southern Democrat issue mentioned before may doom him to a VP position as the highest he can achieve. Could it be a dozen other Democrats who aren't household names? Maybe.
Sorry, I don't understand this.
If you mean that a majority of people polled by Gallup in each of its polls would regularly say they supported the war because they supported their boys, then yes, regular Americans probably didn't pay as close attention to the war as GOP Senator Aiken, who had declared, "We should declare victory and go home."
No, I mean how many people paid attention to Vietnam and the American involvement in that nation. Less than a third of the population paid attention to Vietnam, and similarly many did not even know the name until escalation. We cannot put in our own modern perception prejudices here. Vietnam was not destined to be an area of focus nor was it an area of focus for the average American before 1964.