Many of us have a "roadside assistance" policy to cover emergency road service and towing. There are services that specialize in RVs, e.g. Cloach-Net and Good Sam Assist.
More and more parks stipulate "no repairs", though some turn a blind eye toward low profile stuff. They mostly want to stop the guy who does a major tear-down on the site and the slobs who leave oily residue on the ground or gallon jugs of used oil (yes, some people really do that!). But you will probably end up paying to have a shop do oil changes and such, or maybe seeking out a campground with no restrictions. Fulltimers often have favorite places that meet certain needs and visit them annually.