since you have it all tore apart... I'd get the frame and running gear as clean and serviceable as possible... along with the bottom of the cab.. Hose the whole thing with a decent quality rust resistant paint, put it together and drive it.... collect as many extra parts as you can, and as you get the time and motivation, continue to make improvements to the truck.... it should only take 15 or 20 years to get it looking new again...
