68 4wd conversion...PLEASE HELP
 

Hi guys. So my grandfather is wanting to restore his 1968 lwb 2wd. I have convinced him to swap it over to 4wd. I have seen folks swap to a 73-87 frame in the past but have not been able to find good information on what is exactly necessary to pull off this conversion cleanly. I would prefer to find a 69-72 original 4wd frame but have had no luck so far and I have an 85 CUCV frame available. I do want to run 3/4 ton axles for towing and such, but dont want to lift the truck at all. I want it to be as user friendly for my grandfather as possible. He's 80 yrs old, although still in great health, if its lifted over a couple inches its going to be annoying for him to climb in and out of. Any help or links would be great!!
thanks -Justin