Be warned: The Conejos River in the San Luis Valley is remote, and although you can find a guide, there are no services or rafting outfitters running it, and you're pretty much on your own for access and shuttles (you have to hike a couple of miles through the South San Juan Wilderness to put in). That said, the 52.7-mile stretch from Saddle Bridge to the bridge at state highway 17 can be three to four days of pure trout-fishing bliss, punctuated by Class II-III whitewater and miles-long float-and-bloat sections through high-alpine meadows and past swanky ranches. Because this largest tributary of the Rio Grande runs through private property on its way to Chama, New Mexico, be aware of sections where you can't use the banks, and also keep an eye out for the dozen or so barbed-wire fences strung across the water, as several need to be manually lifted to pass. Put in just below the Platoro Reservoir for an extra 6.5 miles of Class III-IV rapids, and get a good river map to plot out the named campgrounds you want to hit along the way. No raft? There are several points of public access, and the annual Superfly competition is a hoot.
San Luis Valley