What width is your rig with the offroad tires? You want to avoid swapping tires to load/unload the rig if possible (obviously). Buidling a ramp to clear the inner fenders isn't a big deal. the bigger deal is the width of the rear door.
As for height, usually the door of the trailer is about 5" shorter than the roof of the trailer, make sure you measure the door height, not roof height. For loading the rig, do you have a front and rear winch that you can suck down the body with? That will help for clearing the door.
bumper pull or gooseneck? New or used?
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