For "rural" parks this may be an answer:
https://www.forbes.com/sites/kensilverstein/2020/02/10/solar-powered-electric-vehicle-charging-stations-are-just-around-the-corner/?sh=4813e61320f6 Cost is 30 K for a single unit that accommodates two BEV's. These are available now and they are entirely self contained. I do not know if they are 400 volts.
I'm certain redoing a parks electric system to accommodate BEV charging would be an order of magnitude higher, as far as costs go.
I'd expect to see leasing and/or rental agreements.
