[john2000] I use soap and water (ZIP Car Wash Soap/Wax) and 303-Protectant. The trick is to not let it need a good cleaning. If you use a protectant that is easy to aplly you will be more inclined to use it often.
[Ken] To get black streaks off the RV, go to a Walmart Store and get Simple Green. Spray on and wipe off, just that easy. My RV Dealer told me about that. He sells Black Streak Remover, but this works much better.
[Sid] If dealing with a real dirty job, the best product I've used is Industrial Purple cleaner (Available at Home Depot). It works great with little effort. I have used it on cars, boats and my camper. Caution: Strong solution. Rinse well after use and wear GLOVES!