We do not currently own a MH, but are in the market. We have rented class C's in the past from Cruise America. When we rented, they would tell us to try and park as level as possible, or the fridge mi...
We run our Fridge on propane while going down the road, and going up the road too, and no issues yet after years of RVing. But we keep it reasonably level when parked to keep gasses from accumulating.