Thirty miles per hour on a diesel pusher should be no problem. Now if it was a gasoline motor home, then I would not even attempt it. I had on my first coach which was a gasoline motor home the four air bags which some poster said helped. It does stiffen the ride, but the weight of a gasoline motor home is a lot lighter then the diesel and that is why they are all over the rode with cross winds.
Thirty mile per hour wind should not be bad for your coach. Now forty mile per hour cross wind you will start feeling the buffing of the wind and it is best to avoid it. High winds tend to rip up the awning gears at times and when they come lose, they can do a lot of damage to the coach.