Flagstaff to Sedona would be MUCH more scenic. The trip down Oak Creek with the views of the Sedona Red Rock is fantastic. Not a trip you would want to take between Memorial Day and Labor Day as the traffic is heavy when you get near Slide Rock state park (great place to cool off on your ride).

Legally you can only ride I 17 south until you get to Pinnacle Peak Rd. In reality you would want to start riding the frontage roads when you get to Anthem.

If you want to HTFU the ride previously described from Phoenix - Wickenburg - Prescott - Jerome - Sedona - Flagstaff would expose you to less traffic. This would include a ride up and over Mingus Mountain. You would definitely want a camera on this trip...

There is lots of glass and radial tire wire bits on the shoulders of the highways down here (not to mention lots of cactus thorns) you'd want to make sure you have some spare tubes and patches.