I visited this park for the first time recently, and really enjoyed
this particular trail (despite the 95º weather).
The cache is placed near the junction of 2 trails, on a section of
the Bay Area Ridge Trail.
I hiked up the Ridge Trail from the Sprig Lake trailhead, then
went down the Merry Go Round Trail. That's about a 4 mile round
trip, but there are at least 3 other caches on the route as I write
this, and a great picnic spot at the top. Along the way you will
see views of the Coyote Valley, and just some beautiful forest.
The cache is an ammo can, wrapped in burlap (5/07: the burlap
has gone walkabout, so for the time being it's just a plain ol'
ammo can), with stuff kids will enjoy. It is hidden just off to the
side of the trail (keep at least one foot on the trail while
searching).