First check your toads owners manual to see what the manufacturer instructions are for towing behind a RV.
Generally -- front wheel drive vehicles are no problem to tow on a dolly with the front wheels on the dolly. Some FWD vehicles can be towed 4 down with no modifications. Your owners manual will let you know.
Most All Wheel Drive vehicles normally can't go on a dolly. Some can be towed 4 down, some can't, depends on the vehicle. Again check your owners manual.
Keep this hard and fast rule in mind. It doesn't matter what advise you get on here, the correct answer to "How to tow my vehicle behind my motorhome?" needs to be answered by the vehicle manufacturer.
Incorrect towing methods on a dolly or with 4 down can lead to thousands of dollars in damge.
Check your owners manual!!!