Welcome to TRS
Ranger is rated at 1/2 ton, 1,000lbs, although you may want to add an overload spring to each leaf to make it a level ride for full time weight.
Keep weight LOW, close to the bed, narrow wheel base and high center of gravity is a bad combination.
Wind load from the front will kill MPG, so build out over the cab and angle up not straight up, you can use it as storage area.
Wind load from the side will flip you over, so keep it low profile as much as possible, a "popup" is a good way to do that
Swap bars can help you keep a straight line driving in windy conditions.
Tiny house Ranger video here:
www.youtube.com/watch?v=4K6rSTeUOT4
Bed removed seems like a better way to do it
A newer full size truck would be better, and the newer engines get better MPG than many smaller engine Rangers