Although few have hiked the full trail, it is a fact that the Rocky Ridge Trail extends from the south end of Moraga to the west side of Danville/San Ramon. Much of this trail is very lovely, with spectacular vistas in several directions, and nary a sign of civilization in sight. The entire trail is approximately 10.3 km (6.3 mi) one-way, and can be hiked in 2.5 to 3 hours.
NOTE: To hike on these trails, you must obtain an EBMUD hiking permit, which is available here.
The recommended trailhead is Rancho Laguna Park in Moraga -- GC64XM9.
This particular geocache is located at the summit of the first incline from the Moraga side (i.e., from the Rancho Laguna Park trailhead). There is a lovely view in all directions.