You're looking for a container about the size of a 35mm film canister. Log only. BYOP.
This gentle, sunny trail begins just east of the National Renewable Energy Laboratory, but don't use the NREL visitor parking. Instead, go east a bit to find a parking spot.
This is a favorite access trail because it is gradual slope faces south, meaning that it dries faster than trails that ascend the mountain from other directions.
After you've found this cache, keep moving and search for other caches on top of the mesa. The views of Denver, the Rocky Mountains, Golden and Green Mountain are worth continuing your walk.