In 1973 I bought a new 18' Winnebago Brave with a 318 Dodge industrial engine (yep, they actually made a class A motorhome that small) and I flat towed an Opel Cadet behind it. In 1992, when we were full time RVers, I bought a new 40" Bounder motorhome with a 460 Ford gas engine and first flat towed a used Isuzu pickup truck, then traded for a new 1993 Ford Escort Station Wagon with a manual transmission, which of course, I also flat towed. I only had the proper lights on the towed vehicles, no brakes, and no problems. I've seen and talked to RVers with the tow dolly and with the trailer, and if I ever do it again, I'll still flat tow. It's so much easier to hook up, unhook, park, etc. Look at the RVs on the road. How many are using dollies or trailers vs. the number flat towing. BUT . . . any of the 3 ways work, so I'd said it's up to your personal preference.
I see some others responded while I was typing.:laughing: