Actually, I agree with most of what you write.
I do think Nixon had an affinity for the corporate crowd and the well-off, and vice-versa, but agree that that was in large part because of his party and ideological leanings. I think you're correct that he never blended in with such people, but I put that down not to political differences but personality and background: he had grown up poor, and while so had people like Ike and Romney, Nixon had never had business success or been in command of anyone. This doubtless gave him feelings of inferiority among those who felt at home with the establishments types of that era. Nixon was never a "mixer" anyway -- as he himself said, he was something of an introvert in an extrovert profession, and he was a loner to boot...qualities that ultimately helped lead to his undoing as President. I think the relationship between him and the corporate crowd/upper classes was mainly a marriage of convenience: they basically had similar agendas and Nixon envied their success and wanted to emulate it, but clearly he was not one of "them", nor was he blind to their limitations and shortcomings as individuals.
It's intersting that the exceptions you mention, at least people like Rebozo and Abplanalp (among others), were also guys who had been born poor and come up the hard way, so Nixon shared more similarites in outlook and character with these men than with others of similar economic status.
For some reason I wasn't thinking of Kennedy's Catholicsm as a factor that set him somewhat apart from many if not most Americans, but of course you're right about that, and it was a major issue in 1960. (Amazing to look back on now, isn't it?) Still, I'm not sure how much Kennedy himself thought his religion made him an "outsider" in American life. He obviously recognized it was a negative for many people but I wouldn't really say that that made him feel he was not of the social or political mainstream. (He certainly recognized he was not of the economic mainstream.) LBJ had to combat anti-Southern prejudice, even as President, but I think he never thought of himself as an outsider. As for Nixon, I actually do think he may have thought of himself as an "outsider", but in his case I think that was largely either a political ploy (he was forever inventing enemies, beyond the ones he really had) or, again, his jealousies (real and imagined) of people who had "made it" (financially), as opposed to his poor-boy background...something he also tried to use for political effect throughout his career. But all this, again, was more a product of his tortured personality than reality. I never heard of any American, pro- or anti-Nixon, refer to him as an outsider of any kind.
I agree with your revised comments about the normal day-to-day experience of white northerners with blacks, though I suspect it was less a matter of frequency of their interactions -- though that was important too -- as it was the manner of these interactions. I think most northern whites' dealings wiht black people 50 or 60 years ago was limited to having them doing "menial" jobs (waiters, cleaning people, garbagemen, that kind of thing) at a time when there were very few blacks in corporate offices, or in retail businesses that served a lot of whites.
Nixon, yes. Kennedy, no. Russell was nothing like Kennedy.