We loved the entire day we had on the GC Railway Train. The beginning started out with the cowboy shootout, then we boarded the train. We loved the "old time" passenger cars that we booked. Our car had an attendant that not only served a breakfast (on the way up) snacks, but also gave us really interesting info about the surrounding area. We enjoyed the singing cowboys that came by on both directions.
Lastly, the best part for the kids (ok, and the adults) was the train robbery by horse riding bandits. Super fun live action that is interactive. I would highly recommend going to the South Rim on the train.