If that were me, stuck in Bakersfield with a van that had been
overheating all the way south down the Central Valley and one that was now
running very badly and still running real hot...I don't think I'd try to
take the van in to LA.   The Grapevine is really a difficult pass, harsh on
any vehicle..An 'ailing Vanagon'? that can't hardly get down the very flat
central valley?  Not likely to make it over without a "Kaboom!"

  Then say you were lucky and did get to the top, you would then be IN
LA....trying to negotiate the freeways, not a very good place to have a
breakdown, either....There are parts of LA (or any big US city) where
pulling off the freeway onto a surface street is NOT a good idea...

  I've 'been there' in similar situations...no money, car problems, gotta
get somewhere...It's not at all pleasant and sometimes you don't make
rational decisions but in the end you get through it...

   You may have to decide...do I go for it and if she blows, I just grab my
guitar and walk away?  Or as others have suggested, leave the van in
Bakersfield somewhere and come back for it with some money to fix it's
problems rather than risk blowing the whole thing up and losing it all....

   Broke and broken in Bakersfield in mid-summer....Ugg!

  Good luck, keep us posted on the outcome.