Hank,
The only charter that I am aware of that has actually been advertised publicly is the Lerro Productions event in May. That event is geared toward photography as opposed to a fan trip.
With regard to the cost of bringing the locomotive to Colorado, remember that the primary purpose is crew training in the operation of oil-fired locomotives, which is significantly different than coal firing. The Lerro charter, and any other special trips or regular operations in which the 18 might participate are just side benefits, not the primary reason for its visit. If the D&S had not committed to restoring a K-37 with oil-firing, the 18 would likely still be in California.
/Kevin Madore