I have 2 friends that tow their 16’ boat with outboard and trailer ON TOP of their toad pickup. 2 ramps for the wheels: On one the wheels rested on the truck rails and the other used a narrow axle and the wheels rested on the truck bed. A third center rail extended the trailer tongue above the cab. Boat and trailer were lower than the MH height. An electric wench behind the bed extended up to a pulley on the center rail, forward to a pulley and back down to attach to the trailer. Easy to raise/lower the boat/trailer, stow the removable ramp sections, add a few tiedowns and away they would go. Consider the extra weight involved for your MH.
Or a avid fisherman could haul 2 boat/trailer combinations with his pickup!
OR
