I have always been somewhat fascinated by the Salton Sea and it's history. I am heading that way(not in the RV) and was thinking about cutting over and checking it out. In trying to find info online...
I was at Slab City in February. Salvation Mountain has volunteer care takers and is well taken care of.
There is an effort to clean up Slab City and there are some really nice sections. They have a memorial dumpster, but have trouble getting funding for it. Water is available from the Internet Cafe.