O'Leary Peak is a lava dome volcano, not a cinder cone like Sunset Crater Volcano.
The hike is along a roadbed, which is rough with pot holes, rocks and eroded sections. You may take your pet on this road on a leash. Summer temperatures can be fatal to pets left in vehicles.
There are a total of 6 switchbacks to the tower, which is not on the Peak. The peak is O'Leary's western summit. To hike it, get off the road between the two summits and hike up until you reach the top. This is the most difficult part of the climb. The tower sits at 8,916, and offers fantastic views. You can see into the Inner Basin of the San Francisco Peaks, into the crater of Sunset Crater and to the north you can see the Painted Desert. The photo above, taken in June, 2009 by Brienne Magee is of the San Francisco Peaks from the lookout tower at O'Leary Peak. Click image for full-size view.