RE: How far gone is too far gone?
I guess it comes down to how much skill and resources you have. If you can get it for $400 and can do all the work your self it might be. I have a 65 fastback I am restoring for a customer right now. I replace(most was already cut out) rear frame rails and torque boxs, fenders, quarters, doors, floors, transition pan, wheel wells, parts of the front frame, all front engine bay aprons, rockers inners, rocker outers, Parts of the firewall and a few other small parts. This is just the metal work. Now if I was doing it for my self I would have under $4000 in metal and when done basically a new car but you need welder, plasma cutter, and a few other tools to help out. You would be ahead ordering the complete floor pan ($450) and transtion/ trunk pan ($420) and complete rear frame rails ($450 pair) and you now have the floors and frames in complete with the only seam to weld between the floor and transtion pan. In the end it depends on you and how much you like the car and how much you can afford and do. And if you do go ahead and get it a good tip is to get it all tacked together and bring it to a frame straighting shop and check it before finish welding it (saved me on a couple of really bad projects that looked good and measured up right).