>>1576767On the east coast, Congaree is small and neat, as is Isle Royale. Acadia is more populated but worth the trip imo.
Big Bend is large, relatively empty and very diverse (water, desert, mountains).
Mount Rainier is very cool and relatively less occupied than Yellowstone, Yosemite etc, alot of people go missing there though.
Redwoods is like being in a cartoon with the size of the trees, and there is enough space to get away from people (just mind the cats and the hippies in the underbrush).
Bryce Canyon, zion, arches and capital reef are relatively empty and close to Grand Canyon, they have some of the most beautiful landscapes I've ever seen.
Hawaii volcanoes and Kiloeua and anything in Alaska, Guam or the virgin islands are obviously going to be away from people.
To be honest, state parks, national forests and other wildlife refuge zones have some incredible nature as well so dont count them out when considering your next travel location.