Not difficult, Not terribly expensive to go solar.
Assuming self install it should be about same as a Honda 2000 or slightly more depending on size and equipment.
If the area is basically secure you could just lean them against the RV to get started.
But you do need sun. If you are parked between a large hotel and a high rise office tower shade might be an issue.
This may give an idea what is involved:
Forum Members Solar Installations With PicsWe used to charge $7.50 for a battery charge back in the '80s.
That was minimum labor charge back then for a corner gas station.