[JRTJH]

I would advise against using a truck pressure wash for an RV. There are way too many open vents (water heater, refrigerator (top and side), furnace and others, depending on appliances and design. High pressure water being sprayed against the side of your RV will enter the refrigerator vent causing water damage to the OSB and insulation and possibly cause damage to the electrical components as well. The furnace vent isn't designed for a "lateral spray of water" and you'll probably get a burner tube full of water. If it sits over the summer, you may not have a burner tube in the fall (rust). The water heater may or may not be damaged by high pressure water sprayed into the burner tube.

RV windows aren't really "up to the task" of preventing high pressure water from entering the RV and anybody who has been "over-zealous" with a garden hose will tell you how easy it is to spray water into the coach along the sides of most any slide.

If it were me, the closest I'd get to a truck wash is passing it in the parking lot. I'm really not sure if I'd even want to park next to one with my Cougar......