My town, Alamosa is about 1.5 hrs south of Salida. Great riding around Salida. We don't make it up there very often but just south of Salida is the Rainbow trail which is famous singletrack (and very long, like 100 miles or so). My fav section of that is just south of Poncha Springs on 285 you cross the rainbow trail. There is a small parking area on the highway where the rainbow crosses. WEST it climbs up some switchbacks and then some rocky stuff and then superfun smooth carving singletrack. We ride it up to where Silver Creek (MTB only) trail dumps into the rainbow and then reverse it or ride out along silver creek road back to the highway. We always stop and clear the trail to let the MTN bikers ride by just to be courteous. Yep, Rainbow trail...don't let the name fool you. Especially if you ride the EAST side of the highway to the east and south along the Sangres. *($^&?!(^*(%&. That's all I have to say about that side. Your trials tire will serve you very well here.
http://www.youtube.com/watch?v=VcbXjnAwyrE
Texas Creek is east of Salida and has some sand but a lot of good two track.
Also lots of fourwheeldrive (ie, hardcore, not roads) trails just to the north that can be quite challenging on a bike. Beautiful country full of great views.
You can ride (or trailer) up to Marshall pass and ride the Continental Divide Trail to the North and South (singletrack) very fun and fantastic views. Wow.