There should be no entry criteria at all, no having to ask permission from "authorities" to enter or leave. You move there, and you have to make things work. There is no welfare or "social safety net" to prop you up--make it, or fail.
The only caveat would be: harm others and be deported. Outside of that, live and let live.
Also, there should be no "law enforcement." There should only be security companies, investigation companies, adjudication organizations, and bounty hunting. All services voluntarily offered on the market.
I would like some clarfication if we are to have public land. I assume a free society will have no public land and all privately owned. If that is the case you will set the laws of your own property including trespassing.