The van equivalent of couchsurfing.org. I'm going to go with they probably are flaunting local laws as to where people can park.
This is Vanly where the barrier to entry on the platform is owning property in California.
I think https://freeroam.app/ or https://boondocking.org/ or https://www.campendium.com/ or https://www.boondockerswelcome.com/ or even the OP are much closer to "the van equivalent of couchsurfing"