Detergents removes wax so you may want to rewax afterwards.
I've found Purple Power products works with my power washer on my 50 hp blue tractor/house/and cleaning concrete sidewalks/white plastic 3 rail fencing and pad in front of my garage.
I wash the rv by hand using a soft hand towel or a soft brush made for washing rvs and some type of car wash soap.
Power washers don't remove dried sun baked road grime like hand washing or the brush.
I have used the power washer with the wash and wax on the front cap removing bug splatters.....but I always rewaxed it by hand afterwards