There are many regular RV parks that will not allow non-licensed motorized bikes, scooters, golf carts, etc at all in the park.
You can do the same think albeit at a higher price to make the beach cruisers electric assisted. Probably easier to do with a kit then messing with the little 2 cycle kits. YouTube has the videos and Ebay and Amazon have the kits.
I've been thinking of doing this with a tandem beach cruiser.
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad