I think maybe stripping it down to just a body and wheels. take motor, trans, driveshaft, windows, seats, and all the dash out. Then remove any current rust and spry the inside and out with the spray on bed liners stuff. Like LINE-x, or Rhino. maybe fill any open holes with welded plates and expand a foam. Maybe see if you can get a discount on the liner by the business can leave their logo on the truck.