Traveling To Chama

I've got 3 weeks this July to mosey about the West with only a few stops I have to make. Will have to be in Colo. Springs on the 5th and 6th, and must get out into Kansas to meet up with someone before or after that. Thought a trip down to Chama might be in order after taking in some of the South Park line and hunting down their old locomotives. With such a loose itinerary, can a person just drop into Chama and hop a train, or do I need to book it for a solid date and time? I would like to keep my schedule loose in case anything irresistible crosses my path! Advice? Thanks!