We tow a light weight 2100 pound Toyota MR2 Spyder, the little red 2-seat convertible, using a Roadmaster tow bar & Falcon-II hitch kit. Cost of parts was under $1000. I installed the tow bar and did the wiring myself.
Because it is so close to the 2000 pound limit for not requiring secondary braking, we are getting by just fine. It helps not to add more weight into the tow vehicle to store stuff, and the car has a very low center of gravity, making it a very friendly tow vehicle. We don't know it's back there when towing it. Without secondary braking, we can unhook and be on our way in 45 seconds. Hooking up takes under 3 minutes, making it possible to be done right there on the camp ground roadway. Pull-through and even in some back-in camp sites, I drive the car around to the back of the RV and hook it up on-site while my wife is doing other camp tear-down activities.
A tow dolly has it's inconveniences from that 3rd bulky thing to park on your campsite, to the double-work of hitching up the tow dolly to the RV, then driving and securing the tow vehicle to the dolly. You generally can't do it on-site either. You have to drive both vehicles to an area where there is room to "Do The Process". Also consider you need to store the tow dolly at home when your vacation is over.
I think it depends on your type of RVing. If you like to tour the country on the run like we do, we unhook and re-hook the car every couple days during a 3 week trip. The tow dolly would be a pain for that. If you go to one place and setup to stay the duration of a vacation, then a tow dolly is good as you only mess with it 4 times. Twice at home, and twice at your destination. One positive thing to consider with a tow dolly. It takes care of your secondary braking as it has that built-in. A tow dolly also offers a solution for most people who want to use their front wheel everyday home use vehicle.