Black Forest
Black Forest could be described as an Adventure Ride. It's hard to find and a tough trail to ride. It's remote, in the sense of "barely a trail." But if you've done it all and you're looking to try new terrain, you might have some fun. This lariat-loop ride is 15 miles, with 2300 vertical feet of climbing. It starts from the north parking lot of Park City Mountain Resort (PCMR). Top altitude is around 9000 feet.
Riding notes, lariat loop ride:
0.0   Exit parking lot on gravel road south
        N40 39.245 W111 30.550
        Aim between ski slope and Alpine Slide
0.2   Singletrack on L just below Crescent Lift
        Take Jenni's trail uphill
        N40 39.019 W111 30.505
1.0   Hard right turn onto CMG 
        N40 38.599 W111 30.660
1.9   Keep straight N40 39.005 W111 31.292
2.9   Uphill on DT N40 38.259 W111 31.445
        Immediate R onto ST (Midmountain)
3.1   L uphill on CMG (leave Midmountain)
        N40 38.189 W111 31.511
4.2   L uphill on Thaynes Road (end CMG)
        N40 37.816 W111 32.021
4.6   R uphill on Apex singletrack
        N40 38.015 W111 31.756
5.2   L on Keystone N40 37.783 W111 31.866
5.7   Cross Meadow Road N40 37.640 W111 31.483
5.8   Fork R on Fat Lip
5.9   Drop onto Webster Road
6.0   Straight onto ST as road turns (Fat Lip)
        N40 37.495 W111 31.633
6.7   Join McConkey Rd, go R uphill
        N40 37.026 W111 31.732
6.8   R uphill on ST (Black Forest)
        N40 36.970 W111 31.735
        Switchback climb then descend
7.6   Cross McConkey Rd N40 36.993 W111 31.513
8.4   L on TG N40 37.369 W111 31.028
8.6   L on Midmountain N40 37.516 W111 30.927
8.7   Keep straight as Link crosses
        N40 37.495 W111 30.987
9.3   Keep L (R=Empire Link)
        N40 37.662 W111 30.893
9.8   Cross gravel road N40 37.787 W111 30.793
10.1 L to stay on Midmountain
        N40 37.864 W111 30.895
        Alt = straight to John's Trail
10.1 L uphill N40 37.908 W111 30.839
10.2 R to stay on Midmountain
        (L=to Steps) N40 37.874 W111 30.914
12.0 Hard R on DT
        N40 38.255 W111 31.441
        Immediate R on ST (CMG)
15.0 Back at parking
Finding the trail from the south:
Climb to the doubletrack above the top of TG. (N40 36.428 W111 30.474 for the top of TG, N40 36.408 W111 30.651 at the upper TG.) Follow the ridgeline. Veer R onto ST at N40 36.565 W111 31.248 when the DT goes L around a hill. (Look ahead. Notice the unusual stripe on the hillside? That's "trail" but it may not seem like trail when you get there. That stripe is your target.) When you hit the dirt road at N40 36.582 W111 31.506, go uphill. Go around the bend, take the right fork and climb about 100 feet to N40 36.579 W111 31.548. Look for a faint path through the aspens. As you exit the aspens, follow the overgrown trail-cut uphill along the mountainside. When you hit ski slope, duck left through a cleft in the ridge of dirt and go out to the gravel road at N40 36.846 W111 31.587. Turn downhill. This is McConkey's Road. Go exactly 0.3 miles downhill. Just after you've gone around a corner to the left, the trail will cross. Scout carefully for the trail on the right side of the road at N40 36.984 W111 31.515.
PS: If you have an official Park City trail map, ignore it. It won't help you find the trail, and will likely get you lost.
Getting there:
  In Park City, head south on Park Avenue. Follow the signs for Park City Mountain Resort. At the traffic light where you see a bike store on both sides, turn right on Empire. Veer right onto Silver King. As you see the first parking area, turn in and park there. CMG starts on the west side of parking, just north of the buildings.