I agree with the consensus.
RFK takes New Hampshire with a solid victory, McCarthy is unable to gain traction even if his hatred of RFK gets him into the race, LBJ announces he won't run, HHH gets smashed.
With an early RFK entry only LBJ can stop him and if LBJ doesn't run (which is a probability, despite disliking RFK) Humphrey won't get enough establishment support.
Naturally this changes everything. RFK rolls into the convention with every primary a victory, which with Oregon a win also keeps the "Kennedy has never lost an election" thing alive. Mayor Daley will throw his weight around to support RFK. The establishment of the Democratic Party basically gives in at that point.
Without OTL Chicago, or at least with a much smaller convention problem, RFK rolls into the general an odds-on favourite.
Meanwhile in sunny Miami Nixon is watching his support waver, as there were serious doubts IOTL that Nixon could beat RFK. Rockefeller remains unacceptable, but butterflies could easily lead to the almost-happened "what if" of Miami where Reagan and Rockefeller prevent a Nixon first ballot victory. With Nixon blocked Reagan almost certainly makes his OTL 1976 gambit to announce a liberal VP (Mayor Lindsay, probably) and after a few ballots…