I have had pretty good luck with carfax honestly... However, NOTHING will beat a good eye to check things out. On an RV, there are so many things and complications... So many cubby holes and features. Consider that carfax may cost you $30 for a good report... On an RV, go ahead and spend $100 on a person who can really check it out well.
4 whopping cylinders on Toyota RV's. Talk about great getting good MPG. Also I have a very light foot on the pedal. I followed some MPG advice on
Livingpress.com and I now get 22 MPG! Not bad for a home on wheels.