I use the Hampton Inn at the north end of town, they have a parking area
behind and uphill of the hotel that I use when I have the raft trailer (16') hooked to the VX. They have me park at the very top, against the curb in a curved "no parking" area. Then I park my second vehicle (07 Rubicon) in the first space in front of the VX, so I don't get blocked in. Works great.
That spot should accommodate a 35 footer + vehicle. They are a little pricey $140-150 a night, but their beds are heavenly, full breakfast is included, and they are one of the few in town that have double queens in their regular rooms. My husband and I are river rats as well as 4 wheelers and live only 5 hours away from Moab. We like to run the "Moab Daily" stretch of the Colorado River in the Rte 128 canyon from Hittle Bottom to Take Out Beach. Easy access to that lot as well, with plenty of turn around room. Most people park closer to the hotel entrance down on the lower level, so that upper lot doesn't see a lot of action because of the distance. Check them out online.......might be just the answer.