What a great trail system, and so accessible from downtown! We connected the Sand Dunes, Backbone, Lil Rattler, and Frontside trails and ended up hiking somewhere around 4 1/2 miles. Lots of mountain bikers out, but they were unfailingly courteous, and our counterclockwise loop must not be the most common route as most of them were heading in the opposite direction. Wish the trails were a bit wider, as they were busy, but the chance to gawk at the views made up for the inconvenience of constantly stepping off trail to let others pass. If you like this one, you'll probably also love the Whipple trail system in Buena Vista.