If you happen to end up in Durango - I'd consider:
Junction Creek Campground, San Juan National Forest. A beautiful campground close to town. If you turn left at 25th Street (Across from Durango High School) and travel approximately 3 miles you will arrive here. It's quite attractive with most sites being private. Lots of Ponderosa trees. The Colorado Trail starts here with a parking lot appx 1/4 mile before the campground. Only 15 minutes drive to downtown Durango and the train station. I believe the rate here is $18 dollars a night. It doesn't have running water though...
Or if you are looking for a bit more comfort at a low rate, why not try the Durango Hometown Hostel(durangohometownhostel.com.) It's located up towards Fort Lewis College. A straight shot to the train parking lot down College Avenue. Depending on how many night you stay it's between $22 and $28 dollars.