The dolly might not add a lot of of tongue weight, so I don't think it is quite as bad as a regular trailer. I would likely try the tow setup first, and add bags if needed.
On the other hand, some "upscale" RVs add airbags as standard equipment, and they are really not that expensive; so I suppose it won't hurt, as you can add just enough air to keep everything in equilibrium. However, if over used they could probably result in a harsher ride.
Break-aways may be required by some states. I have one for my towed vehicle, which I flat tow. But it came with the brake kit. Nevertheless, it never hurts to have such a thing.
The only thing that works on a RV is the owner...