You don't know th half of my "scheme" with my Ranger Bed trailer...
A) It's already got sides and a solid tailgate.
B) I have TWO caps (one aluminum and another in fiberglass)
so I can have a roof on it with a couple of cap clamps.
C) all that empty "wasted" space under the trailer is what interests me
(people who know me won't need this explained in Braille

I have two (one 38gal one 44gal) Econoline fuel tanks that fit neatly between
the frame rails Under the trailer. I have a 65gallon tank that is 3" narrower than the bed that will be mounted forward of the bed just behind the "A-Frame" up to the hitch.
That much fuel (added to the fuel in my truck) will allow me to do a round trip to Wyoming on "junkyard gas" with a >350mile reserve presuming I can average
18mpg (a pretty safe assumption)
AND I'll still have the entire 7foot bed and most of the 6foot bed on my
Ranger for cargo space. I will register my trailer for 3500# the empty
trailer is expected to weigh right around 1000#, with a full 147gal load
of fuel weighing another 880lbs that would still leave me 1600lb of cargo
capacity. that's FOUR 4.0 engines, EIGHT 8.8" rear axles or SIXTEEN Mazda
transmissions (more than will actually fit) and that doesn't mention the 1000#
I can still load into the Ranger
Now, if I can find a 4BT cummins and convert to "diesel" and run the truck
on USED ATF....
AD