Hmm..the bars at the hotels won't really be what you are looking for unless you want to pay too much for drinks with nobody else around..Stay wherever and go to the Pickle Barrel, Wobbly Barn or Outback.
the grand has a nice bar if you dont plan to be able to drive yourself. Inn at the long trail is nice but way to far from the slopes if you do not have your own transportation. if you do stay at the grand killington provides a bus that goes up and down the access road
Try the North Star Lodge on the Access Road. Beautiful suites and an outdoor heated pool that is awsome! Breakfast is included and I believe they have a bar on site but the Wobbly Barn and Pickle Barrel are real close. We stayed last winter and it was terrific and reasonable.