Follow the old fire road up the mountian. This is a nice rocky VT style climb. You'll see the singletrack on the right after climbing for about a mile. Its unmarked but there is a lead-in to the trail from both up-mountain and down-mountain so its pretty clear. You could also ride further up the fire road 'cause its wicked coming down. The singletrack drops for two miles or so of unmarked trail with some great dips and a couple of logs. At times it feels like you're breaking trail. You'll dump out onto a private road, go down in and then right, back up Spruce Mtn. Rd. to the head. That last climb is a lung buster. Repeat.
P.S. There are always tons of hikers on the fire road section so watch out.
Head East on Route 2 from Montpelier. At the Blinky Light in Plainfield make a right. Bear left onto Main St. and go up the hill past the railroad bed entrance. Make a right onto East Hill Rd. Follow East Hill for approx. 2 miles and make a left onto Spruce Mountain Rd. Follow Spruce Mtn. to the trailhead. (bear left at the Y)
http://www.singletracks.com/item.php?c=1&i=980