Too many variables. The roof has a crown, so the peak height is about over the back seat area. Is it really stock height?
The enclosed trailer has even more variables. Is it really a 6' opening, or a 6' door?
Does the trailer have a dovetail? That hurts. The rear tires will climb up the dove tail before the rest of the roof is through the door. Climbing faster than the roof tapers. So even a 71" tall Bronco, that is only 70" tall at the back of the roof, and the opening is really 72" tall. You still wont clear because of the dovetail.
But if a flat tail, there are better chances.
What is the ramp like? Many enclosed trailers don't have that stout of a ramp/door.