Since the trail to Miller Peak is a spur off the Crest Trail,
which traverses the entire Huachuca range, you have your pick of
routes. Lutz Canyon is the shortest and steepest; Montezuma Pass is
reputed to be the easiest; but for my money, the Miller Canyon
Trail is the best. There's ample parking at the trailhead at the
end of Miller Canyon Road (near Beatty's Guest Ranch), and the hike
is 12.5 miles roundtrip with about 3500' of elevation gain.
The Miller Canyon trail is so well marked that you may never
need to turn on your GPS. Much of the route is shaded by tall
trees. There's usually filterable water available at Bathtub
Spring.
From 1926 through 1991, a fire-lookout cabin stood on the summit
of Miller Peak, and the foundation remains today. The cache is
placed in the base of a rock outcropping 12-15 feet south of the
cabin's former cistern. Cache container is a small, waterproof box
containing a logbook and a batch of handmade lanyards.