That's a great list, and the best part is that even that doesn't even start to scratch the surface. This list looks mostly at larger parks - or at least ones that are big enough to have a website.

Almost every town, even small towns has a park where you can stop have a lunch and move around for a while. I've even found some Interstate Rest Areas that could easily be classified as Landmarks themselves. And of course the only way to find those hidden gems is just to get out there and look!