I had a buddy who had a 4-cylinder Highlander and about the largest of the Coleman popups. He barely made it to the dance with that combo. He had to take it easy in hills or strong winds. A 6-cylinder & not anything more than a 19-footer may suffice. I'd recommend looking into additional tranny cooling if it doesn't have that already. And yes, PM Andy Thomson
at CanAmRV about any particulars about hitch, weight distribution or wheel selections that may serve you better. I've had people 3 or 4 states away appreciate this recommendation. It's opportune that you are so close.