Update 9/9/13 by mtbgreg1:
The Arkansas Hills Trail System is the closest singletrack trail system to downtown Salida... and by that I mean that it begins directly from downtown! Just cross the F-street bridge, hang a right through the fence, and follow the tire tracks to mountain bike heaven!
Arkansas Hills follows the principles of the "stacked loop" design, meaning that the easier trails are lower down the mountain, but as you travel up and out the trails get progressively harder and harder. There are some smooth (but exposed) beginner-friendly trails on the lower reaches of S-Mountain, but higher up in the hills you can easily challenge yourself with super-advanced rock gardens, narrow singletrack, short-steep descents, and a wide array of gnar!
Due to their position in the dry, warm area of the valley, these trails get HOT during the summer... and when you ride them, you'll note the cacti and realize that this hills are actually a high-desert environment. However, those hot, dry summers also indicate that these hills stay mostly snow-free and mild all through the winter, making this trail system (as well as the other, lower trails in the area) a winter destination for the folks from Summit County, Crested Butte, and other locations that get snowed in during the winter months.
While this trail system is a great achievement, the local trail organization, Salida Mountain Trails, isn't content to just rest on their laurels, however. They continue to build new singletrack and expand the mountain biking opportunities in the Salida area every year!
This Network of trails has a bit of everything, and there is really not much elevation gain and loss, Very Moderate.
The new North Backbone is super fun but tight with quick turns, not a super fast trail but you will use your technical skills.
Rattle Snake gets you pretty much to most of the trails, very easy trail not much gain, you might run overs some tumbleweed tho!
Burn pile is a blast to go down hill, fun swooping turns.
Tenderfoot is much more technical but still not much elevation gain.
Front side trail is a great way to descend back down to your car.
Check out http://salidamountaintrails.org/ for maps and other trails in and around Salida!