I'd figure out a way to reattach those joists when not working on a vehicle ....I don't know if you get snow n ice but that stuff weighs a lot ...1 gal ='s 8 lbs
My 70 CORONET is from AZ...sheetmetal is in excellent condition ...interior is fried. The savings in body work MIGHT justify the 5K. I'd drop a B or RB n 727 in this, polish the paint and use it as a driver