Welcome to Stovebolt, KBrown. Have you looked for a donor cab you could use for this truck?
I'd advise finding one, especially if you want to convert to a big rear window. Your cost would also be (probably) significantly less with a donor cab.
I understand if you just want to do the work; the only project I help replace a roof was on a '34 Packard. Bracing bars were welded in to retain the vehicle's form prior to cutting the roof panel off. Plenty of folks will jump in soon with some specific advice; you'll get quick responses if you can share some photos of all this Swiss cheese, or a video walk around of your truck.
Good luck!
Brad
