>>8850028
I hope the increased use of national and state parks will be for such reasons as you mention - leisure, exercise, sport….
A darker idea that comes to mind is what happened, for example, in the Vietnam War - when North Vietnamese citizens who were under bombardment in the cities, in many cases, buggered off to their country's national forests and parks where there were caves and other natural 'bomb shelters' they could use for free.
If Chinese ICBM's managed to get through to some of our cities, people might need to do a bit of what the North Vietnamese did and use the national parks/forests as areas to evacuate to and organize/train civilian militias.