Promontory Butte is a large outcropping from the Mogollon Rim. It overlooks See Canyon and Christopher Creek. Having hiked around it several times, I've always wanted go to the end, and planting a cache seemed very appropriate.
It was a 9 mile round trip from the Rim Road (FR 300) and I was glad to have a high clearance 4X4 as FR 76 was not very good in places. Once I reached the end, I selected a scenic area that overlooks one of my favorite caches, Slick Rock View (GCQ40Z) along the Highline Trail.
Take FR 300 to FR 76, and stay on the main road (don't take FR 76A, 76B, or 76C) until you are within a few hundred feet of the cache. Alternately, you can park at FR300 and make the 6-mile round trip hike to the cache. The really adventurous can park at the Horton Springs Trailhead, hike the Derrick Trail to the Highline, then take the Promontory Trail up to the top, and bushwack to cache and back. This way only involves 10 miles and 1000 foot elevation climb and descent. 
The cache is located right on the edge of the rim. It is hidden in a rocky crevice about 15 feet below the top: there is an approach from the west that isn't too steep. Study the pictures if needed.
This cache is subject to Mogollon Shift.