They don't have much listed for events yet and it does appear there's still some tweaking needed to the schedule. It's possible the schedule for Railfans' Weekend just hasn't been release yet. Their 2020 brochures, are going to be extremely late this year, if they still haven't finalized the schedule and events.
As for the 7470, I recall them saying it will only be operating on Saturday's this year, starting in June. A couple of years ago on this forum the rate per mile was discussed and they're not cheap to run. If I remember, it was around $70 per mile when you include "all" cost, from: crews, fuel, insurance, maintenance & inspections. So with three round trips a day at 11 miles per trip, it adds up very quickly. That and I guess they just don't have enough qualified people to operate the engine.
I still can't figure out why they changed the departure times for the Valley Trains by moving all departures up 30 minutes earlier and moving back the dinner train 30 minutes later. They say some exciting changes are coming, would this have anything to do with them possibly squeezing in a late afternoon departure to Redstone? Just a guess on my part, I'm going off half rumors from last year but it all makes sense if that is the case.
It takes real skill to choke on air, fall up the stairs and trip over nothing. I have those skills.