My favorite restaurant in Keystone! The menu is varied and every item is delicious (at least every one I've tried or seen). As testament to how much we've enjoyed it, the Great Northern Tavern was the site of our Thanksgiving dinner, 3 years in a row.
This is also a microbrewery, but my tastes in beer are so pedestrian that I wouldn't attempt to pass judgment on the selection or the quality.
You can eat in the bar area, with casual food, or the dining room, which features more formal entrées, all done well according to my experience.