Not sure I’d do this as I would expect there to be more people than I’s like visiting at the time I was there but it is an interesting idea.
https://www.washingtonpost.com/travel/tips/map-out-your-visits-national-parks-around-their-free-entry-days/
https://www.washingtonpost.com/travel/tips/map-out-your-visits-national-parks-around-their-free-entry-days/