Sounds like you've got a great trip planned. If you come through Flagstaff, be sure to stop at Odegaard's Sewing Center, a fantastic LQS here. From here you can go to either the south rim of the Grand Canyon, or the North Rim if it is not closed for the winter by the time you are here. Near Flagstaff you can also see Wapatki National Monument, Walnut Canyon National Monument, Meteor Crater off to the east, and let me think.. there are lots of fun things to do and see around here, so it depends on what you are interested in really.
Hope you have a fabulous trip, and if you need any local Flagstaff info, just pm me.