I've got two rooms booked already and they're just about full. I'm so grateful it's been announced and so looking forward to it, even if it's a night short of most festivals.
As for the train, those of you flying in will want to get to Grand Central Station (ask at the airport for the shuttle bus -- probably cheaper than a taxi, unless you share with other fest-goers). Once in the main terminal, go to the MetroNorth counter, Hudson Line. This is the train that will stop at Tarrytown. Make sure, though, that if it's an express train (depending on the time of day), it actually does stop at Tarrytown. I believe so, but it's been a while since I took MetroNorth. When you get to Tarrytown, the hotel won't be too far, but a taxi is definitely what you'll need.
Here's something else. I believe if you buy your train ticket at the counter in Grand Central, it's a tad cheaper than getting on the train and buying it from the conductor, but again, I'm not sure. I do know that's definitely the case if you buy a round-trip ticket. If you actually know when you'll be going back down to Grand Central, you might want to consider buying that round-trip ticket.
This is just great news! I'm hoping to meet lots of you there, at least, those I haven't already met! What fun!