Get a diesel pusher. Quiet, no hump to struggle over, powerful at low RPMs.
And it's important to look for an RV with an engine large enough to math out to 1 HP per 100 lbs of curb weight max. So anything better than that means a nice quiet powerful engine that isn't straining going up hills.
My 15 year old 28,000 lb Winnebago with a 330 HP engine works out to be 85lbs/horse. And though I usually end up at 55 heading uphill starting at 62, there's little strain on the engine. I do actively downshift when necessary.
JMO.
