On that note, what are caravan parks attitudes towards powered camp sites and EVs generally? I imagine some wouldn't be too happy if you used 50kWh over a one night stay!
I charged recently at a remote pub overnight for 15 hours on a 15A caravan socket (although my Gen 2 UMC maxes out at 12A using the 15A tail). Before I checked in the owner said I’d be charged $10 to plug in. When I checked out and asked had he added in the $10 for charging (because I was going to offer $20) he said “nah mate it’s fine”.
Just tell people what you are going to do and most are chill about it!