"Dave", the generator expert at Smith Powerhouse, Inc, recommended using the RV generator and roof air conditioner while underway as the generator uses a lot less gasoline than the dash AC requires. I'm not sure that the comfort level in the cab will be as good as when using the dash AC. We'll try using one or the other or both. Best to travel in mornings and evenings when practical to be easiest on you and your rig. I worry about hot tires pounding on cupped concrete or superheated asphalt highways on hot days.