A moderate roundtrip hike of ~1.8 miles (~45 min) will take you into scenic Cheesman Canyon via the historic Gill Trail. Although the net elevation change is zero, the terrain rating is a reflection both of distance and some mild up-and-downs. Cache is a blue un-camo'd tea box; please bring your own pen!
From the parking area, follow the trail ESE as it crosses a forest road (look for the marked trail sign on the other side), and continue along to a marked placard located at N 39 14.357 W 105 15.442. Along the way you will see up-close the damage caused by the Hayman Fire that ripped through here in the summer of 2002. Once you reach the placard, continue S along the trail ~5 min to the cache.
The rock formations in Cheesman Canyon are impressive; there are numerous boulders strewn about that are as large as a house. Trout fishing in the Canyon is spectacular as well, and as such this section of the S. Platte River has been designated a "Gold Medal" stream, which comes with special regulations (catch-and-release, artificial flies and lures only). Catching the fish here won't be easy though, as they all have Ph.D.s in entymology!
Since Cheesman Canyon is primarily a fly-fishing destination, this cache has been stocked with over a dozen flies. Please remember to bring your own writing implement and cover the tea box appropriately to keep it sheltered from the elements. I hope you "cache" something!