Very good question....
First of all 13K-15K for paint and body....Ya right.
If the car "truely" is a rust/bondo bucket,sell it.Let someone else deal with the headache.
You are in the rust free capitol of the U.S.
There are some good deals out there right now,where cash is King. There was a beautifully straight Demon on here,in SoCal,that just sold for around $3K
I am in SoCal as well,and see straight/clean cars all the time going for
$2K-$4K. Always smart to start with a clean platform,and being in Cal,there is no reason not to.
My .02
