The west end of the Hidden Valley Trail starts off from the trailhead at Broadway Street and visits what constitutes a valley in open farmland. Heading along a bench, this section of nearly level trail is smooth singletrack. There is no shade on this dry route, but instead you get plenty of grasses, yucca and chattering prairie dogs.
Upon reaching an intersection with the Degge Trail
, continue hiking straight and slightly downhill. The trail curves gently down to the low point of the valley where there can be mud and standing water after a heavy rain. This is easily hopped over. Start the ascent up the other side of the valley negotiating the only area where you'll need to watch your footing. This slope has loose gravel and rocks. This is also the closest approach to the firing range, so you'll likely hear unsettling shots nearby.
At the top of the hill, the views south are of the impressive flatirons and the views west take in the Boulder County foothills. The remainder of the trail covers flat open fields pockmarked by prairie dog holes. The trail ends at a gated fence line at the junction with the Mesa Reservoir Trail
Eagles, northern harriers, red-tailed hawks, deer, coyotes, prairie dogs, rattlesnakes, bull snakes. Yucca, grasses.