Possible buy of 63 Valiant. Need Opinions!

wait, so are you giving up the valiant to get the truck? or giving up the truck to get the valiant?
either way its probably a straight-up trade....the question is what are you going to have more fun with???
as far as your body panel questions, there are a few things available, but not as much as for B and E-body cars...you'd probably have to pretty much scrounge for everything.
The main pitfall is going to be RUST RUST RUST. that is the one thing that is going to cost you the most time and money to fix. Check the areas around the torsion bars, that is where the most critical place is structurally for rust.
-Tim