Think I'm screwed

I agree with all the above. This is not a good candidate for any but an extremely experienced car person. Mr. Rust is never found without all his buddies, Rust, Rust, Rust and Rust. (Sounds like a law firm, eh?) There is no way the crossmember and floor look like that and not have it basically everywhere else. Rust can be a quick deal killer.

I'm a reasonably competent soul for the most part with a full shop, a lift, and access to LOTS of tools. I wouldn't touch this car with a ten foot pole. It has every appearance of being a soul-sucking money pit. I don't mean to rain on your parade, but I think this is sound advice from everyone. If someone wants to restore this I'd sell it to them in a heartbeat even if I did so at a loss.

A crusty old guy once explained to me that good decisions are often based on experience. Unfortunately, experience is generally gained from having made poor decisions. You bought a turd that will cost you some dough one way or another. However the good news is I suspect you will not buy another one.