If the frame was shot, then I would put a Coilspring chassis, defender/disco axles under it, and a V8/5 speed manual/LT230 for the powertrain. Oh and power steering.
Instead of a V8, might go turbo diesel if I could find it/wasn't priced the same as a bar of gold.
What I've found with a project car is that it just HAS TO WORK. Otherwise, you won't drive it. If you've gotta spend 20 minutes pre-tripping the stupid thing, you won't drive it to work, to the grocery store, etc. It sits and when a vehicle sits, that is when crap goes wrong with it.
The key is to make the truck as turnkey/plug n' play/user friendly as possible so throwing a cooler in the back and hitting the mountains doesn't require second thought. Or grabbing the keys for it off your key rack instead of your DD doesn't make you hesitate. Now you can drive it and enjoy it. That is what makes a project vehicle successful.
Well, in my eyes at least.