A popular trail in all seasons, Dry Canyon above River Heights is one of my favorite local hikes in the fall. You only need to hike a short way to reach the fiery maples, then you are walking between splendid fall color (as far as I've been at least, and probably farther!) Enjoy black and gray cliffs and rocky crags at other times of the year, but generally no flowing water, except in spring. This is indeed a "dry" canyon.
The trail is slightly rocky in places, but nothing difficult. There are no stream crossings before the cache area. You may encounter mountain bikers and horse riders. Motorized vehicles are not allowed. There is ample parking on gravel at the trailhead, but no other facilities. I believe that the lower parking area is generally kept plowed in winter. Hunting might be permitted further up the trail (I am not sure.)
Please watch out for rattlesnakes, especially in spring!
The cache is located just the other side of a barbed wire fence, but if the gate is locked (which I have never seen happen), you should still be able to reach the cache location with a little bushwhacking and rock scrambling.
Congratulations to grumpywombat, who got to see fantastic fall colors while heading up for the FTF!