I don’t know about the National Parks system. But I think that would be a super good thing to do.
Last year I rode 2,800 miles and the year before 2,500 miles. That’s like coast-to-coast and back.
Of course that spread over two years. A young-er person could do it shorter.
Those of us in the Cream City are fortunate to have politicians supporting expansion of the Oak Leaf Trail system in Milwaukee and surrounding areas. It makes for beautiful rides throughout the southeastern Wisconsin area.
https://en.wikipedia.org/wiki/Oak_Leaf_Trail