In order to give at least a partial answer to your initial query, the Galveston Railroad Museum has a pair of operational and Amtrak-qualified F7 "Warbonnet" locomotives (not original ATSF equipment, but rebuilt and painted in that scheme under BNSF license). They are available for charter; the base rate is $6000 per day, per unit. You supply crew and fuel, plus whatever the railroad charges for you to operate over their tracks. There are also two Amtrak-certified coach cars and a buffet/dining car; they charter for $2000 per day per car. Again, you supply crew (and food for the diner) and make arrangements to have them hauled.
As with most things in life those charges are negotiable, especially for extended charter periods, but that is where the discussion will start.