Dinosaur National Monument straddles the Utah/Colorado border in a pretty remote part of the West. Most people visit the Utah section of the park to see the dinosaur fossils, but I stayed in Colorado to see the canyons and the Yampa & Green Rivers.
The Harper’s Corner Trail is an easy 3 mile round trip hike not to be missed - you’re about 2500 feet above the confluence of the two rivers in an semi-arid desert canyon.