I'm curious, specifically, if I need to address rust spots on all panels, would a worthy alternative be to buy a parts car of all the same color to bolt and weld the parts over to?
I stopped in the local body shop to see about my newest Caddy's rear doors. His est. is replacing with good doors, prep and painting could run about $1400. At the North end, $1800 to $2000.
I'd seen recent TV news crashtest results showing $5000+ repair bills for 20 mph, and/or 5 MPH crash tests done on new cars/vs. SUV/trucks etc.
It seems that his recommendation, avoiding salt using States to source your used/new sheetmetal and replacing the old is the lowest cost option. In terms of the ASC mods, I think the rear flanks are the biggest concern...but welding seems possible to mate the old and new and then refinish the rust on those (deck lid/spoiler)
BILL