I used to build 4x4's like that back in the early to mid 90's. Most were Jeep CJs or Wagoneers from the 70's and early 80's. We did a few Ford and Chevy trucks. It was great fun to see them out in the woods being used to climb rock faces or climb down them. Tires are the most important part along with having extremely low gearing in the transfer case or using double transfer cases to get down a cliff like that. Rear steer helps but it wasn't something we got into much.