I may be wrong, but I don't think UHaul will rent a tow dolley or a trailer to be towed behind an Explorer. I know they won't rent one to a ranger owner (me).
hope you have your own towing equipment or somewhere that you can borrow it. the previous owners of both my Explorers scorched their trannys by towing other vehicles; one with a towbar, the other on a trailer. the back bumpers both looked like an elephant sat on them. neither had a Class III hitch.
however, I have towed an explorer from SC to MS with my Ranger. just don't expect to use OD unless you want to replace you tranny if you actually make it home.
I have towed my F-150 4X4 behind my Ranger, but only 60 to 100 miles one way.
it's a dangerous situation, towing something heavier than your vehicle. if you go the towbar route, always make sure the towbar is lower at your back bumper/hitch. if the tow bar goes upward toward your tow vehicle, a sudden, hard or panic stop will jack-knife you and possibly cause a rollover.
slow and easy works for me, just don't get overconfident and waste two vehicles.....
....jjf