dumb newby dumb question

Do not ever plan to tow any vehicle until and unless you read in the manual that came with that vehicle that it can be towed 4 wheels down. It usually is listed under recreational towing and not emergency towing.

If the Edge is front wheel drive, then, yes, I would recommend towing it on a dolly. (I know nothing about the Ford Edge vehicle)
If it is rear wheel or all wheel drive, then no, it probably should not be dolly towed.
Another consideration is the weight of the Edge/dolly combination. What is the towing capacity of the hitch on the Vegas motorhome. It is quite likely either 3500 or 5000 lbs.
Tongue weight is not an issue for dolly towing, the tongue of the dolly puts very little weight on the hitch.

what does your owner's manual say about towing behind a motorhome or recreational towing. that is the only "valid" source of information.
bumpy