What I did up in Alaska when there was 14" of snow on the roof was to take my phone with me in case I fell, a 2'X 1' x 3/4" piece of plywood that was kind a scruffy on one side so it wouldn't slip too much on snow. And wore a pair of knee protectors. Climbed up the ladder with a broom a swept off the powdery snow as much as I could from the ladder. Then brought the plywood up. Climbed up the rest of the way with the snow shovel. Then kneeled on the plywood for most of the work basically pushing a shovel full at a time off the nearest edge. Move the plywood every once in awhile to reach new areas of course. In the very middle of the RV, I'd just stand...wearing waffle soled boots.
I've also tried sweeping it off from a ladder on the side of the RV and that sucks. Pretty much have to climb onto the roof to get the majority of snow off anyway.
Just work slowly and realize that every flake doesn't need to be removed.