I have a "pad" in my yard where I park my camper when it's not in storage. I run an extension cord from the garage and use an adaptor similar to this:
Epicord 15 Amp Male to 30 Amp Female Dogbone Adapter RV Electrical Converter Cord Cable (15A Male - 30A Female) https://www.amazon.com/dp/B07T66XTZQ..._CLKFFbFK81T3J
I don't use it to run the air conditioner, the microwave or any other high draw items while it's parked in the yard. Basically, it keeps the battery charged and allows me to use the 12V lights while it's parked on the pad.
If I was totally serious about it, I would have a 30 amp "peg" installed in the "pine clump" next to the pad and run a buried cable from the panel in the workshop that's beneath the garage. Maybe next year. In two weeks (or less) my FF will be in the storage barn .