What did they do during the 10K service? The oil and filter cost me $130 or so I believe. Very easy to do. It does sound like too much $ to me. But I don't have any other motorhome service experiences to compare it with.
Cost sounds about right for a dealer, I got oil and filter from NAPA and still cost $140 to do it myself. You also had the fuel filter changed and tires rotated. The fuel filter is about $50-80 and is hard to get at. I think you got off easy.