Did some research on the tandem tow dolly (brand name). The plate the car sits on is adjustable, you slide it back to offset the weight of the bike, golf cart you are hauling. I also talked to the local welding shop owner yesterday and he believes the tongue weight would be around 3-400 lbs and recommended going with a heavy duty hitch on the dolly and a 2 5 /16" ball on the motorhome. He didn't think the weight would bother the motorhome like it would a truck. Guess the only way we are going to answer this question is get it done....