The northwest corner of Colorado is pretty wide open without much in the way of mountains. Dinosaur National Monument is worth a visit but access is limited if you're on two wheels, unless you're on a dirt bike. If you're coming to Colorado from the west there's a good chance you're on US Highway 40, and will come by the town of Dinosaur. The country here is wide open and hilly, and by the time you ride on to Steamboat Springs you'll be in serious mountains.
Click at the edges of the map to shift to the adjoining portions of the map.
Here's what it looks like at the state line on CO 13 just south of Baggs, WY. The first shot is looking into Colorado and the second is looking toward Wyoming.

