Begin at the Hidden Valley trailhead in Spanish Valley. Hidden Valley's first half mile, nicknamed "Barney Rubble", is extremely difficult. This short trail section is legendary. It is the sort of futuristic ride that is rapidly vanishing in the current hysteria to make every trail--including legacy trails--"flowy" and easy. For the vast majority of mountain bikers, Barney Rubble is only ever going to be a steep, rugged, grovelly hike-a-bike that raises you to the gentler sections of Hidden Valley.
Hidden Valley lies in a secret cleft between the Moab Valley and its defining southwestern wall. The trail in the valley is a mellow roll through a gently sloping meadow. Once in the valley, simply follow the obvious singletrack as it gently slopes upward. The trail steepens and gets difficult as you climb a short way up to a small pass with a broad view to the west. There is a great petroglyph panel a short walk away on the cliff face to your right.
From the pass, the trail abruptly roughens up, widens, and heads down. The riding gets MUCH harder and more technical now as you drop down, climb back up, and contour right to eventually meet up with the Moab Rim Trail
for a descent to the Colorado River.