^^^ That's Vaguely right. Though McCarthy at the start of campaign got support from people who wanted to escalate the war, not end it. That's because he acted as an "opposition to LBJ" weather vain. Also there was a decent amount of blue collar support for McCarthy in the Primary as there would be for McGovern four years later - especially in areas with weaker unions.. but that dissapated hard in the general of 1972, probably due to "Acid, Amnesty and Abortion". Of course there was always an element of hardcore in the Student movement who would never support a presidential candidate for the Democrats.. these were the people at Chicago and probably make up a good deal of ageing hippies themselves.
Also I don't really see McGovern as an elitist... the people he was (unfairly) associated with though...
Your first point about McCarthy receiving support from pro-war Democrats is true, but only in the very, very early stages of the campaign, primarily in New Hampshire and Wisconsin before LBJ dropped out. Also, I don't think you could really characterize them as "McCarthy Supporters" because they never really supported him. Most of them probably ended up supporting Richard Nixon in the general election, with some Southerners going to Wallace and a few staying with Humphrey.
Blue collar support for McCarthy was limited at best, at least until RFK jumped in and took away pretty much all the blue collar support. McCarthy's core base were college students. In the run-up to the Wisconsin primary, McCarthy barely campaigned in the ghettos, and during a debate with Kennedy before California, his plan to essentially move people out of the LA ghettos and into Orange County was criticized by Kennedy and others. Of course, McCarthy enjoyed slightly more support among rural whites, but still nothing like he enjoyed among the educated elite.
The college students who would never support the Democrat at all were a lot smaller than people think, IMHO. These were mainly people like the "Yippies" and some of the more radical members of "SDS," along with black nationalist movements like the Black Panther Party and SNCC (or what would become the radical SNCC if they had not segregated already, I can't really remember). Contrary to popular belief, at the time the Chicago protests were happening, most Americans strongly, strongly disapproved of the actions of the protesters. In fact, most though the police exercised the right amount of brutality or were not brutal enough. Also, the effect of causing people to stay home because of the riots in Chicago is minimal, with something like only 1% of Democrats refusing to vote because of what happened outside (and inside) the convention. (However, you should note that the overall effect on the race from Chicago should not be pushed aside.)
Your final point about McGovern not being an elitist is one I have to agree with. In 1968, McGovern actually attempted to stand-in for RFK at the convention, receiving a I believe a little under 200 delegates. However, just because he wasn't elitist doesn't mean CREEP didn't try to paint him as one.