Recommeded cleaning for MOST RV roofs is:
Mop, Bucket, Spic&Span, garden hose, water.
Sweep: any loose debris, Same as you would a kitchen floor, only on the roof you just sweep it off the edge, no need for a dustpan/distbin.
MOP, again like the kitchen floor, Rinse with hose letting rise water run off, Then wash sides (normal car wash procedure)
Caution: DO not mop yourself into a corner unless that is the corner the ladder is in.
One suggested modification to above.
instead of a mop.. I have one of those fancy "Van Wash" brushers This is a common carwash brush with a telescoping handle,, I think it works better.
in days of old Fuller brush sold a Window Washing brush,, This used a standard mop handle (Theirs) and it too would work well. I do not know if they still have it but any Janitorial Supply will have one.
I like the van wash brush better though. Any auto supply The one I have has "Flow through" but I do not use that feature.
The above assumes a roof you can walk on,, My first PUP that was not the case, but I could wash the roof standing on the ground using that brush so not a problem.
Home is where I park it!