Grady, our MH had a fiberglass roof and I washed it one time and realized I was standing on a sloped sheet of ice. When we were full timers we would use the Blue Diamond and other truck car washes at Pilot and Flying J. It only cost about $25 to tun through and you can add extras like wax occasionally. If you do that regularly it will keep it pretty clean and a lot safer than walking around on top.
I discovered some time ago that I don't bounce when I fall !