Northern Arizona:

Aspen Nature Loop

This trail—at the base of Snowbowl—offers a super easy hike where one can see views of the San Francisco Peaks and the Grand Canyon.

https://www.fs.usda.gov/recarea/coconino/recarea/?recid=55064

Kachina Trail 

This trail filled with aspen trees and located right below the parking lot of the Arizona Snowbowl. This moderate-to-difficult 10-mile hike gives one views of the biggest firs and pine trees that anywhere else in Arizona.   

https://www.fs.usda.gov/recarea/coconino/recarea/?recid=55112

Hart Prairie Road

This biking trail located 10 miles north of Downtown Flagstaff takes you on a colorful view through the many aspen trees of Arizona and high-altitude meadows while displaying unbelievable views of the San Francisco Peaks. 

https://www.mtbproject.com/trail/5500184/hart-prairie-loop