Once inside the parks there are well marked hiking trails that take you deep into nature.
I basically followed the Rocky Mountains from Alaska down through the Canadian provinces of The Yukon, British Columbia and Alberta. The mountains here tower above you and in the summertime, daylight is plentiful.
Into the lower 48 I explored Montana and Wyoming and the worlds first and possibly most famous National Park -Yellowstone.
Travelling further south the lush landscape gives way to deep canyons and strange rock formations in the deserts of Utah and Nevada.