Pioneer Mountains Scenic Byway is Montana is fantastic and included in the Great Divide MTN Bike Route.
http://https://backyardmontana.com/a...t-you-can-see/
And the portion of the Trail of the Mountain Spirits scenic Byway from Silver City to Gila Hot Springs in southwest New Mexico is remote, quiet and challenging. Featured in stage 5 of the Tour of the Gila.
http://https://www.newmexico.org/pla...ntain-spirits/