Cleaning the solar panels

When traveling you can pull into a truck diesel pump station. Many times they have little, err, big step platforms, about 4 steps high or 3 feet, that you easily walk up and gain height to reach the top. They also have squeegies on long sticks so you can reach all the way across your roof.
Not all truck stops, but some.
Keep in mind you will be getting in the way of commercial truckers, so look for low traffic times.
Sometimes the regular gas stations will have diesel pumps around back and have these long sticks too, but not always steps.

ANother solution is those telescoping ladders if you are allowed on a ladder. You can reach the roof without getting on the roof. A long squeegie stick will be needed if panels are further center.
Rain will get some, but always leaves a dirty film.
When you are up there wipe on some "Rain-X" or other similar windshield treatment to prolong the ability for rain to clean it, keeps stuff from sticking to the glass...

Look into a RV wash guy that would come to the RV park or even to your home and just do the roof for you every so often. If the cost is too high for a complete RV wash perhaps they'll just do the roof for you and then you do the wash but you'll have dirt running down the sides if you don't tackle the sides as soon as he leaves.

The panels do need cleaning every so often. Rain doesn't do it.

I think being on a ladder or any other platform/device and trying to reach the panels would be more dangerous than just getting up there. If your panels can be reached just by climbing your RV ladder and walking down the center of the RV it's safe as long as you don't have to walk along the edge.

At some point one needs to get on the roof to check all the caulking and roof surface to maintain your RV in good condition.

Rain seems to help mine a lot, I don't do ladders or roof!