The literature I cite says the majority of senior national security council and DoD personnel were convinced that introducing regular troops is the necessary step by mid 1965, though McNamara, MacGeorge Bundy and George Ball all proposed having the option of capping troop levels at less than 100,000 (though obviously McNamara and Bundy let that option slip away). And these were all original Kennedy men, natch.
But even then those lot were all counter balanced by the Joint Chiefs and Westmoreland, who wanted a 'go large' policy by that point (even if interestingly Westmoreland had been more in line with the civilians during '64).
Okay, even if one speculates about Kennedy putting Bobby in as SecDef at the beginning of the second term, and rearranging a bunch of other appointments on the NSC and at the subcabinet level in both DoD and State, and, most importantly of all, giving absolute priority to the CIA's more fatalistic analysis about Rolling Thunder (they thought it wouldn't accomplish much) then there's the brickwall situation of "we are NOT going to plan on some sort of Dunkirk evacuation of our 16,000 men from a defeated RVN." That has to be taken for granted as American policy bedrock. No way round that. And no way he sees the extent of this coming in '64.
My guess is a 'mild escalation' by Kennedy involves giving Westmoreland somewhere around half of what he initially wanted (the general wanted 175,000 in the first big build-up), firing him when he complains and replacing him with a more 'optimistic' field commander (is Taylor still okay for that?), not going for comprehensive pacification across so much of the RVN, instead merely plugging one hole at a time with USMC/Air Cav/Airborne, and making Rolling Thunder into a more Operation Linebacker-ish campaign. I think this allows them to hold on for a couple years, though it means a U.S. 'surge' down the line; mid to late 1967? No doubt they label it a 'go long' policy.
The only other options are the full Johnsonian escalation, Dunkirk, or enter negotiations that allow the 1975 endgame to take place sometime shortly after mid-'65. I discount the possibility of either Dunkirk or proto-Ford taking place under President Kennedy.
Forget the specifics of of what we do or don't think about Kennedy the man. No POTUS elected in 1960 is adopting a 'go home' policy for Vietnam in 1965, not if they've got to the point where 'go home' means turnning their back on the largest peacetime combat advisory mission America has ever had.
Very interesting, and very plausible. Definetly seems like the kind of policy Kennedy would follow.