Like traffic fines in some European countries, but with a lottery system as well if the number of potential visitors is high enough, with no substitution of people to eliminate reseller market for lottery. Some national parks in the USA already have to limit visitors and state and county and local parks in California that I have seen during the pandemic had to put limits on people visiting and a lot of that was free. Most of the US solutions are based on first come first served or reservations with first come first served so equity of any kind is not addressed otherwise.