Ride the chairlift at Snowbowl ski area. It runs until mid October. Fantastic views from 11,200' up.
Visit Williams, 30 miles west of Flagstaff on I-40. Fun old Route 66 town. Visit Bearizona drive thru animal park (walk thru area as well). Deer Park petting zoo is also nearby.
We usually stay at the Grand Canyon Railroad RV park which is next to the Railroad which runs to the Grand Canyon.
Meteor Crater east of Flagstaff on I-40 is interesting. The crater itself isn't much to see but the space museum is worth the stop.
In Flagstaff is Lowell Observatory which offers tours. It has an over 100 year old telescope thats unique with its rather simplistic construction. Lowell is also where Pluto was discovered.
