The trails in this open-space preserve just south of Golden, which abuts Denver metro, are well known to mountain bikers but severely underhiked. The 5.5-mile exterior loop makes for an awesome hike that you can bust out in about 90 minutes if you hustle. You'll likely encounter many bikers at the beginning and the end of the trail, especially if you go in the evening, but the path leaves plenty of room for you to pass them as they grind up the inclines and for them to whiz by you on the downhills. Start on the Apex Trail (ignore the cheesy Western-themed family fun park off to your left; it'll disappear from sight about a quarter-mile in), which offers a mellow incline through a narrow valley, and then take a sharp right up Sluice Box Trail and zigzag up the hillside – this is the toughest part of the trek. At the top, follow the Grubstake Loop, which tours through deep forest and then pops back out on the front side of the hill for view of the city. Continue straight onto Pick N' Sledge for an easy descent back to the Apex Trail. This final stretch is easy to run if you want an extra challenge.
More Information: For trail and park details, visit jeffco.us.