If you ever want to get some of your money back out skip the safety features and go pre-1975 anything. That's saleable out here in Calif w/o smog, so huge potential customer base. Do a decent job with decent paint and you MIGHT be able to get most of your money back when you sell.
1974 Camaro or any El Camino would be very nice. Lots of parts and support. A-Body (Chevelle, GS, Tempest, etc.) would be a good choice. EFI Big Block with a 4 or 5 speed would make an impressive ride.
As stated, any pick-up truck or panel van would do too
Something like a Chevy LUV truck with a small block could be very quick and fun
Or, the universal thing, a CJ Jeep with a small block and decently built suspension (compliant with articulation) will be big fun and good seller. Same for an IH Scout. Early Bronco is already out of your price range ...
You have lots of choices, but if you insist on "modern safety features" you are sort of going against the grain ...
You could also look at a 1988 or later Porsche 944 which does have all your required safety features and is a decent sports car for a project. Parts are plentiful in the used market and there are plenty of rust buck donor cars to swap stuff from. A turbo will get the machine's attentions...