I wish I had seen this post earlier. You are probably on the water now.

I have never fished the NY part of the Battenkill but I've spent a lot of time over the last 30+ years on the Vermont side.

Your Catskill fly collection should suffice. If they've gotten as much rain as I have (I live in PA now) I'd be worried about the water level and how muddy the river is.

Let us know how you did!