My soon to be 14 year old son has decided he wants a 67-72 chevy truck as a project

First thing we saw was a 68 1/2 ton, 4wd, small block 4 speed.
Flat bed with ladder racks, very rough cab & front clip, motor not running.
Only real plus was the 4wd, could buy for under $500 but way too much body work.
Going to look at a 68 GMC tomorrow, C-20, 2wd, 454 4 speed.
Running but has noise - guy thinks maybe a wrist pin ???
Body is very good on this one - originally from Idaho.
We're in PA - good bodies are very hard to find anywhere in the northeast
Any ideas on what this truck is worth?
Thinking maybe we could build a 4wd by piecing these 2 together.