At the very end of last season, I went to a PSIA event at Mt. Snow and stayed at the Mountaineer Inn ( http://www.mountaineerinn.com/
) . My criteria were the same as yours, and I was pleased with all aspects of my stay there.
As I recall, they gave PSIA members a substantially reduced rate. I presume they will do the same this year. Be advised, however, that some (many?) of the rooms don't have a TV. I enjoyed the peace and quiet, but YMMV.
My event was so late in the season that there was hardly anyone around Mt. Snow. As I drove up, the parking lots of all the nearby lodging and restaurants were deserted. However, when I finally got within sight of the Mountaineer, I saw that their parking lot was filled to capacity, and just about every vehicle was a Subaru with a roof top box and a PSIA or ski area employee sticker on it. It turned out that all of us cheapskates had called around and had independently discovered that the folks at the Mountaineer were offering the best rate of the nearby lodging.
One fun aspect of the stay was the good natured and humorous reactions of the two or three non-PSIA guests at the lodge (apparently, new recreational skiers) to being surrounded by all these ski instructors endlessly talking shop, waxing skis and adjusting bindings while sitting crosslegged in the hallway, etc. I think these folks wound up getting many hours of free lessons from instructors who just couldn't restrain themselves from teaching.
Have a good time at the event.
Tom / PM