I paid $1600 for mine, and the only real difference being that mine is an H-Code, and my engine was seized. OK - mine was worse... I'd reluctantly start with $3500 (only if the engine really runs), but not a dime over $5K. You're buying a project that someone's decided is too much to handle for themselves - you're doing them a favor, basically.
If the floor pans are that bad, the firewall and/or cowl is probably going to need repair as well.
Lower quarter panel rust, usually means outer wheelhouses, trunk drop-offs, and there will probably be some soft spots on the rockers. Tail light panel rust means the rear cross member and part of the trunk pan will need attention as well.
"Disassembled + all parts appear to be there" = you have no idea if they're all there or not. Be careful - there are lots of things that can be missing and hard to replace. Of course, if they're toast anyway, it really doesn't matter.
Click on the Facebook photo album link in my signature below, and look at what you're up against (well, maybe not as bad as mine). I'm over $40,000 in replacement parts & body/paint alone - and did all my own labor (almost 2000 hours, which multiply by a conservative $50/hour and that's $120K labor).
It's going to be a LOT of work, requiring a LOT of fabrication/repair skills that you either need to have or will have to learn unless you want to go broke paying someone else to do it all.
Just my $.02 - having been through it all. Hope this helps!
Aside from all that: totally restorable - but with a black interior.
