Mike,
With all the hinge pockets rusted away, you have a major task ahead of you. There's really no need to brace using the hinge bolts, etc. You can tack weld bracing just about anywhere that has solid sheet metal.
With your description, I would hesitate trying to restore that cab. Like bartamos said, finding a replacement cab would be WAY less work.
Good luck to you. Once you get into it you'll be at least an adequate welder.
