I have ridden the towers on a road bike (lost my frame pump on the way down due to crappy roads, almost need a MTB to ride the pavement up there). I have also ridden halfway down the Desert Classic trail over lunch one summer. I need to get back and do more. My problem is my mountain bike predates the days of suspension so a lot of those trails are hard on the old hands. My favorites right now are the Hawes trail area over by the Salt River, and the Jacobs Crosscut trail in Lost Dutchman State Park. Still pretty new to the MTB scene in the valley having mostly roadbiked the last 4 years (I grew up in Flagstaff and have canvassed everywhere within a 15 mile radius of there on my MTB in the 90s).