What follows is one guy's opinion, developed following my first visit about a month ago and then trying to learn as much as I can about the state of the property and its future...
I have to agree with Bill - one steamer is more than enough for now, given the short section of operable track. The shops are the crown jewel, and need to be stabilized. Apparently the famous boiler stacks have to come down soon, as corrosion has rendered them unsafe. The blacksmith's shop has similar stability problems. Seeing that it's all wood framing, a fire protection system is also urgently needed.
Ideally I think the most urgent need beyond that is to find the funding and appropriate management to get the EBT sold to some party with the historic mindset to really restore and preserve the property. The Kovalchicks, while they've done a great thing by keeping it running, are still at heart a for-profit entity and (from my impressions) aren't going to invest the money to stabilize much of the non-operating parts of the property "for history's sake." I believe that setting up some sort of preservation trust or public/private partnership to own and manage the property would be far more critical - in the long run - than any individual piece of equipment or structure.
In the meantime, the Friends of the EBT have done wonderful things where possible. I don't mean the above comment to in any way diminish the work they do. Even while I was out there, they were working on the conversion of another steel box to a passenger car, so as to take some of the daily workload off of the historic wooden passenger cars.