In 2002 we towed 1990 Honda Accord from Texas to Anchorage and back without brakes without incident. I know that is not considering having a tow dolly but we were able to go up and down some pretty steep grades using the engine transmission to slow us along with the brakes. Our MH then was a 1999 Bounder with the V10. Loud and slow up and nice and slow down. What a great trip.
I think you can go wherever you want with your rig as long as you are aware of your limitations and plan ahead, but now that we have brake assist on the car it makes it safer to travel. Drive on, have a good time and get brakes whenever you can.