According to my son, the Red Lion Inn in Norman Rockwell's town (the name escapes me - I'm old) offers good food and a fringe benefit. He said he and some friends from work were eating there one evening when a guy walked in, went over and picked up a guitar from the corner, and started singing and playing. Turns out it wasn't karaoke night - just James Taylor amusing himself for the evening. (He lives nearby, and does this occasionally just for fun.)
By the way, my son uses mostly fleece for his ski and kayak escapades, but also uses down for general wear and for his sleeping bag. (He doesn't hike much anymore - says paddling is easier.)
There's a really good outdoor shop just outside Pittsfield called the Arcadian Shop - your son might want to wait until he gets to college, then stop in the store and ask them what people use. (I've bought several items there, and found them to be very well-informed and helpful; so has my son.) There's also a couple of shops in the towns right on the AT, though I've never been in them. Finally, there's an Eastern Mountain Sports in the mall just north of Pittsfield where you might be able to get advice (but I'd be a little leery since it's a chain.)
Also, for what little it's worth, I hike in Ohio, Indiana, and Kentucky. The temperatures run somewhat similar to the Berkshires (except the lows usually stop just above zero), and it's an equally wet and humid climate. (We get periodic thaws, so the snow doesn't pile up the way it does up there, but other than that, it's very similar damp conditions.) I use fleece to hike in, but carry a down sleeping bag and a down vest for camp. I wouldn't want to hike in down (too hot), but I've never had any trouble using it in camp. I do wear a down vest outside to blow snow at home, and don't have any dampness issues - but I'm not working up quite as much sweat as when I'm hiking, either.
I'd probably send him with what he's got, and an awareness of the damp conditions he's heading into. He'll quickly get a feel for what works for him, and can tweak it from there.