This is a point-to-point trail over 8 miles long. There are no road crossings and it feels pleasantly remote for being so close to the city. You can start at Genesee Mountain Park or Windy Saddle Park along Lookout Mountain Road. The Windy Saddle parking lot is fairly small and fills up fast, so get there early. There's portable restrooms at the trailhead and new vault restrooms under construction.
If you start from the Windy Saddle parking lot side, you'll start off on Lookout Mountain Trail
for about a quarter mile. The Beaver Brook Trail start is well marked and will veer right while the Lookout Mountain Trail
continues up and to the left. Beaver Brook is hiking/running only. No mountain bikes or horses.
The trail starts with great views overlooking Windy Saddle to the north. You'll cross two boulder fields and a lot of up and over, rocky boulder sections in the first mile or so before it opens up with some smooth singletrack through shaded pine forest. At about a mile and half, you'll turn south and descend down for the first of a few creek crossings. From there it's rolling hills in and out of exposed sections with great views and more shaded pine forests.
At around mile 4, you'll see Gudy Gaskill Trail
which loops to the north for a 2.4 mile detour and then reconnects back to Beaver Brook. At mile 5, it gets fairly steep as you climb up and top out to a flat section with several rock outcroppings and a few options for overlooks with views of Clear Creek to the north. Then, it's a loose, rocky, steep descent to the Genessee Park side.
Lots of wildflowers along the way, and watch out for cactus along the trail. You can hike the whole thing (with a pre-arranged shuttle at the other end), or do shorter out-and-back sections, or construct loops with other trails and return to your starting trailhead. This is considered one of the best hiking trails in the foothills of the Front Range.