I have been all over the American West-- in car though, not on a bike. From that perspective, you should really consider making the desert southwest one of your desinations. The Colorado Plateau area in N. Arizona and S. Utah has some of the most unique geography on the planet. While the Rockies and Sierras are both excellent choices, you might want to diversify a bit by choosing just one of our mega-ranges and seeing our deserts. The Sedona, Arizona area is unbelievable and probably has excellent cycling. I would look into it. You don't have landscapes like that in Europe.

Here's a pic of me approaching the Colorado River crossing a few years ago on a desolate road in Southern Utah. The rock formations in in this four-state area are epic.



I have been through the Sierras and the Rockies and love them both. However, for the sake of diversity, you should mix things up. There are a lot of good things going on here.