Mostly single track. First part is all up hill and a serious leg burner. The rest varies from tight technical trees to down hill sections to banked turns to hill climbs (not in that order but it has a ton of variation) Do it more than once to get a full work out. The second time will be faster. You can bypass some of the trails/ loops by going straight on a two track. If you always stay left you should do the full 6 miles. There is also a downhill course and a skills area.
Get off 131 at the west river drive exit and turn left onto west river drive. Take west river drive until it turns into cannonsburg road and stay on cannonsburg road until you see the entrance for cannonsburg ski area on your right. When you pull into the drive stay toward the left on the pavement and you will see a mmba kiosk with a trail map and other info.
http://www.singletracks.com/item.php?c=1&i=3435