I spent most of yesterday on top of Everest - our Everest brand 5th wheel - scrubbing the top as part of an overall cleaning.
That's 333 square feet of surface area, give or take, not counting the tops of the slide-outs, the cowlings on the air conditioners, etc.
I scrub the top with a soft brush on an extendable pole, and a mixture of a little detergent and a lot of Clorox. It's not exactly a full day's work, but it's as much as I want to do in a day.
Today I start on the sides.