We cut the back bumper off and made a good squAre tube bumper, we even pull our double ski trailer loaded with 35 gallons of fuel jugs, takes two people to lift the tongue, never had any problems with it, except the $350 ticket for being over length on interstate lol
I wouldn't think there would be a problem with the rack itself, my concern would be more of the frame at the rear spring mount. With that much length and that much weight, I would think it would be prone to bending.