I did a comprehensive write up of this trail over at Trails Offroad:
Gardner Canyon Road/FR#92 Highlights
Highlights: Gardner Canyon Road/FR#92 - Sonoita, Arizona
If you are looking for stunning scenery, shady places to picnic or camp, and the possibility of spotting wildlife or even a rarer fleck of gold in the stream beds, Gardner Canyon is for you. This is an ideal trail to try out your off-road vehicle for the first time.
Easy Peasy - graded wide road until the Apache Springs Ranch Fork. Then narrower, curvier and bumpier until the end. A couple stream crossings too.
It's so smooth and strait you might want to drive it Baja style, but don't, there will be a lot of opposing traffic.
9.1 miles, about an hour, if you don't stop too much.
About 40 miles from Tucson. From Interstate 10, head east to mile marker 281, Arizona Highway 83. Head 29 miles south.
Previous AZFJ Runs to this Trail