Bill,
Railfest starts on August 22 and goes through the 25th. The Eureka will be there, Goose #5, the Casey Jones Railbus, and possibly the Popcar club will have some members there. On Saturday the 24th, there will be a "Swap Meet" in the roundhouse. On Sunday, there is a garden railroad tour available along with the D$S yard tours. If you call 970-247-2733, they can make reservations for whatever.
Hope this helps. I looked at the web site also and didn't get much info from it.
Erick