Some of us have towed overweight - but not like that!
My only experience with a U-haul car carrier: Neighborhood dealer wouldn't rent one to me, he said they have to see six-lug wheels on the tow vehicle.
Across town there was a larger U-haul dealer. They quizzed me what I was going to tow since their trailer bare, was nearly at my early Trooper's 2,000 lb rated tow capacity. I told them a small garden tractor. Ok.
I loaded my first Yanmar, the YM240 shown in my sig below. And tried a brake check. Fine, that smoked the trailer tires before the Trooper's. Ok. A few miles down the road I realized I could detour to Port of Sacramento to use their truck scale. 8,500 lbs!! Either U-haul's trailer or the Yanmar was a ton over what I expected. The Yanmar's rated weight is 1,800 lbs plus the unknown weight of its loader, the Trooper alone only weighed 3,500, so I was pulling 2.5 tons.
That was a very slow cautious tow to get the trailer 100 miles to the ranch. No issues, aside from way under-powered on a few grades. I wouldn't do it again. That Trooper was great but this was asking too much of it.