I couldn't find anything at the Acura site or at Edmunds. It took some doing but I found relevant numbers on
www.kbb.com for the Acura MDX. It says the curb weight is 4515# and the GVWR is 5798#, leaving a load capacity of 1283#. By the standards of my initial argument that actually does have fair capacity for passengers and hitch weight. But I do think you will get a broad consensus on the Forums saying, "Don't do it."
106" wheelbase and 6 cylinders is just too puny. I do have a friend with a Highlander and it is a respectable sized vehicle when you stand next to it. He tows a large Coleman (now Fleetwood) pop-up camper and absolutely feels at the edge of what that vehicle can do.
Please don't fall into the abyss of "a dealer says so" if you get that from an RV salesman. Making a sale might be too tempting, though
knowledgeable sales people that I have met wouldn't let this get by them.