High profile vehicles rock and roll in the wind. Unless you are talking Provost. I live in the mountains. I haven't had any problems. If you want to zip up mountain grades at 75 of course you'll need a diesel. Unfortunately if you do buy gas front and rear anti sway is almost a neccesity along with a steering dampener. One importantant thing to consider in a gas MH Is wheel base to length ratio. The longer the wheel base the more stable you will be on the highways and the less maneuverable you will be in tight areas like parking areas. If I were FTing I would be looking at a used Provost which is a true bus chassis with a diesel. We are out 4 or 5 months a year and our gasser is just fine.
BTW higher end gassers put more insulation over the engine. Less noise and no heat.You can of course add that insulation yourself.