This is a series of four stacked loops. They are all fairly easy, but very bumpy with plenty of small, mostly loose rocks. There are maps at most intersections, but some of them are faded and not always legible.
From Alamosa, take 160 east until the intersection to 150 heading north to the Sand Dunes National Monument. 10.7 miles north (about 3 miles before the Monument) there will be a dirt road heading east toward the Sangre De Christo Mountians. There shoudl be a sign indicating the road to Zapata Falls. Follow this road about 3.5 miles to a large parking area. There are numerous trailheads on the downhill side of the road linking to the loops.
http://www.singletracks.com/item.php?c=1&i=5270