You have to be careful with pressure when they have bump outs. The water may get behind the seams and actually start to flood inside the RV. I am also careful around windows, vents, and storage area doors for the same reason. Scott and Carey's advice is very good. I usually stand 5-7 feet away for that very reason. Nate at Northern Lightning washes hundreds of those things, and many of them are over 1 million dollars each. So his customers are very particular. Maybe give him a call too?