If the car was wreked in front, the engine was usualy running.
Rust stains indicate use of water instead of coolant, and that often means it needed constant refill from a headgasket leak.

What did the fluids look & smell like?

hook up some radiator hoses, and fill the cooling sustem with compressed air...
you can get a pressure guage all the necessary fittings for about $20 at a hardware store.it should hold 15 PSI for quite awhile. you will hear air escaping if there is a big leak. spray suspect areas with soapy solution and look for bubbles.
Good luck.