Of those I've been to - this is just for scenery and overall experience, not cycling:
Redwood
Sequoia/King's Canyon
Yosemite
Acadia
Bryce Canyon
Arches
Grand Canyon
Mt. Haleakala
Zion
Smoky Mountains
Canyonlands
Capitol Reef
Shenandoah
Volcanoes
Gettysburg
Mesa Verde
Mammoth Caves
Great Sand Dunes
Joshua Tree
Petrified Forest
Painted Desert
Everglades
I'm sure that some of the jewels that I haven't been to would come in high on the list. Yellowstone, Glacier, Isle Royale, Rocky Mountain, Olympic, and several of the parks in Alaska are all on my "must see" list.
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