From the parking lot head south as this trail begins to climb, and climb very high into the hills. You don't climb Picket Post mountain but go around it's western side as you climb and eventually descend into surround hills. If you don't like climbing don't bother as this is difficult. Eventually you'll summit the high point and lose ground to the trail's end but I didn't make it that far. The trail continues onward as the Arizona Trail does eventually reach to Mexico.
Trailhead marked off US 70 couple miles west of Superior.
http://www.singletracks.com/item.php?c=1&i=4996