Start at base lift and go right onto trail into woods. Actual sanctioned races have been held here, and trails are X-country skiied too. Some trail markings. The trail actually goes up the ski mountain in a counter-clockwise fashion, summits, goes out behind the mountain a bit, and circles back to the base on the left (if facing the ski area). All said, there are epic climbs, very rocky technical sections at the top, and crazy downhills. Not very well known, may have it to yourself, just be cool while you are there. There are some houses close by and we don't want to lose this place to ride. Good luck not breaking your pedals here!
From Plattsburgh, drive west on Rt 3, take right onto some road (sign for Beartown Ski Area), take left onto Jersey Swamp Rd. Go down a ways till you see sign on right for Beartown again, take that right and go till you see ski lodge on left. Best thing to do is go to a gas station and ask how to get to Beartown Ski Area.
http://www.singletracks.com/item.php?c=1&i=1587