I make the round trip from AZ to WI at least once a year. I've done it with every possible RV for many years now. When I was younger I did about 700 per day. Now I try to keep it to what I can do on 1 tank of gas (that's about 400) in my Cls A.
500 is ez in a car but it can be a lot towing. If you go on the freeway the trucks and potholes will leave you fatigued. Back roads (I35-US50/56) or US54 are draining too with the constant quartering winds going west and the buffeting by the cattle trucks. The biggest issue though to me is refueling. I dread it because of the length and access hassles.