I agree... take the whole trip.... but on the other hand, I don't like to ride the bus late in the day! The family's exhausted and it's late when you get back to Chama, so supper is a bust (after you wash the soot out).
I prefer to get up early, ride the bus from Chama to Antonito, and ride east-to-west (just like tourists who rode the Circle years ago). There's plenty of time to grab a cup of free coffee, look at the stuffed equipment in Antonito, and watch them dump coal into the tender with a front-end loader.
I can hear some people say, "but you don't get to hear the loco exhaust whuffing while you struggle up the hill!". But you do get back to Chama with plenty of daylight left to wander the yard.
The catch is that you should drive to Osier the next day, walk to Rock Tunnel (about three miles) and catch the train coasting out of the tunnel and enjoy the tourist's faces as they peer down into Toltec Gorge.
Tom