You can also consider flying in to Durango, Colorado. Rent a car from there - and head east 2 hours to Chama. Durango also puts you at the Durango and Silverton, and a nice loop drive from Durango to Ouray over the Million Dollar highway after you pass Silverton. From Ouray, go just a bit to Ridgway. There is nothing left of the DRGW branch from Ouray to Silverton -- a county road (#17 called N Oak street leaving Ouray northbound) sits on top of the ROW just west of the river. Ridgway has its own railroad museum, bits of the old RGS station, and is the location of the filming of John Wayne's true grit. Non-railroaders will want to ask where John Wayne shouted "Fill your hands you sons of b****s (https://video.search.yahoo.com/yhs/search?fr=yhs-symantec-ext_onb&hsimp=yhs-ext_onb&hspart=symantec&p=john+wayne+fill+your+hands+true+grit#id=1&vid=599c4378842c43b4f4fe12ae4468b592&action=click).
Look for courthouse rock just northeast of town.
Meanwhile, you can follow the old RGS west over Dallas Divide into PLacerville, then up through Ophir, Trout Lake (water tank and last remaining trestle), Lizard Head Pass, Dolores( Goose and rebuilt station, Rio Grande Hotel), Mancos (not much -- East Mancos is in private property), and back to Durango. Mesa Verde is off this loop near Cortez/Mancos.
Lots to see.
If you do fly into Denver and rent a car - consider dropping down to Colorado Springs, then up to Cripple Creek and Victor, down the old Florence and Cripple Creek ROW to Canon City, then Salida, and down the valley to Alamosa (169 plus a business car there), then Antonito. Chama is next. Your could do Durango, the loop above, then up to Montrose and east on Highway 50 to Black Canyon of the Gunnison, Cimmaron (some railroad stuff there, plus the 278 on the bridge down the canyon north of town. Continuing East on 50 you get to Gunnison - you will see 268 there. At Sargents, detour over the dirt road over Marshall Pass (or take 50 to see what's left of Monarch). Salida is a former RR town - rails have been quiet for more than a decade, then 50 down to Pueblo and back north. (OR you could fly in to Colorado Springs, but then you'd miss the Colorado RR Museum in Golden....).
Lots to see - you could easily spend 4 weeks doing it all. But distances are very long compared to your experiences in (Europe?). Keep the gas tank full at major towns, and driving after dark in the mountains may bring you an opportunity to see deer or Elk on the highway (be careful).
Have fun! Good luck planning an interesting trip.
Don
