Thank you very much! Indeed another good insight. Yes, the case is more like no.2 but is not like totally "private" place, will be a public place visible and open for everyone with a van/motorhome.

He have an empty land like for 30 vans or something like that and he want to use it, because in the area there's no dedicated service like that, only some regular camping sites and are always full during the summer. The owners of those campings are always pissed off with caravan campers because they occupy the places and they cannot get regular campers that stay longer.

So they decided to do this place DEDICATED only to auto-caravans with full services.

So yeah as far I see, should have somebody at the entrance to charge each visitor. That will be the easiest and simple method.