This is a great singletrack but it is merciless. Just don't make it your first ride of the year. No problems following this trail, just follow the most obvious route. Though not overly technical, the grade doesn't level out at all. ~ 1/2 mile from the forest service cabin on top you come out onto a road which you follow to the left. Great downhill coming down the same route. <br />
Try it as a loop; from parking area follow road to Rat Lake access road and follow it to the right. Go past Rat Lake and follow the road to the forest service cabin. This is a driveable road the whole way and adds ~7 miles to the ride.
From Big Sky drive north on Hwy 191 ~ 18 miles to Storm Castle access. 1 mile from hwy are two trailheads. On the left is Storm Castle trail, on the right across the creek is Garnett Mtn. trail. I've ridden Garnett but some ride Storm Castle also.
http://www.singletracks.com/item.php?c=1&i=4172