I don't know how much to trust polls, but if Bustamante is ahead significantly, to only sure way to prevent his governorship is to get enough people to vote "no."
Having other candidates drop out may not help much, because everyone sees the same polls and will vote for whomever they think has the right combination of ideals and electability. If supporters of Candidate X think X has no chance, they may decide to vote for someone else without needing X to drop out. Those who vote for X anyway probably wouldn't change their vote even if X withdrew between now and the election. Voters are pretty smart, so they can decide for themselves how to vote on election day.
In that sense, I sympathize with Peter Camejo (Green) in his support of runoff voting, although I don't know which format he supports, and I don't know if I would like that format. Of course, I disagree with Camejo on almost everything else.
I think if voters see that Mcclintock has dropped out the majority of his votes would go to the only man standing between bustamante and the governor's office. I also think he will do the right thing, what's best for the party and drop out asking his supporters to do the right thing by defeating bustamante. Of course we may have to wait until March to find out.