Let me try to add to what Keith said.
"Colorado Springs to Chama?"
If you like to drive at 75 mph and not go over so many passes, the faster way is south on I25 to Walsenburg then US160 to Alamosa then US285/SH17 to Chama. However, Keith's way is more scenic.
"Durango to Colorado Springs via Ridgway, Gunnison, etc?" There are two ways to do that. US550 to Montrose. US50 to Gunnison and Poncha Springs (over Monarch Pass at 11,312 feet). US 285 to US24 and US24 down to the Springs. Or you could stay on US50 to Penrose the take SH115 to the Springs. From Gunnison it is about a 2 or 3 hour drive either way. If you would like to see the Tennesee Pass line and the new Royal Gorge train, stay on US50. If you want to see the old grades of the South Park and Colorado Midland do US24.
"Also, when would be the best time to catch the Chama-bound train on the C&T?" If you mean chase and not ride, then you first catch site of it at Los Pinos at about 2:30 or 3:00PM. You then can follow it to Chama where it arrives about 4:30.
"Is there anything to see (photograph) in Chama yard after the train returns?" This is a trick question, right? Start with all the MOW cars that we have been restoring, then work your way up from the south storage tracks, seeing the stock cars, box cars, rotaries, and on and soforth. Duck into the engine house and roundhouse, but be careful. Then go north to the coal tipple, two-spout tank and oil tank cars at the oil loading dock. Oh, there is the 120 year old depot too. But remember the sun will be setting earlier at the end of September.
"Is there anything to see in Durango yard in the evening? (And will they let me see it?)" Last I knew, you had to be conducted on a tour for $5. I doubt they do tours in the evening. It is really hard to see much from outside of the fence. Can someone else confirm this?
