The Bill & Marion Certain starts at the Cecil Ashburn Drive Blevins Gap Trailhead and ends at a TV tower atop Green Mountain. Most of it is part of the original Spacewalk Trail. The first 50 feet is rocky and technical; it's usually easier to hike-a-bike through this section. After that, it ascends up to the Sugar Tree Trail
. This ascent has a few rocks and roots, but it's easy enough that an experienced mountain biker can pedal up it.
At the fork with the Sugar Tree Trail
, hang a left and continue up the mountain. Most of this section is steep and rocky. The experienced mountain biker will be able to ride some of this, but few people will be able to ride all of it. Mountain bikers are advised to use discretion as to when to hike-a-bike and when to ride. There are steep drop-offs on the downhill side for much of this section; reroutes around downed trees and rock features and roots also abound. Some of this section is also eroded. When you get to the area where trail runs along the stream, you'll be near the top and you can breathe a sigh of relief.
At the top, you can see Bailey Cove and Jones Valley on the right. The trail continues along the top of the ridge. There will be a re-route around a downed tree, and after that, the fork with the West Bluff Trail
. Keep left at the fork to stay on the Bill & Marion Certain Trail. The trail continues along the ridge, and is mostly smooth with a sandy and natural surface. A few downed trees may be present on the trail; if you can't clear them, just hoist your bike over them. Soon you'll come to the power line easement, where you can see Big Cove and Hampton Cove below you. The Power Line Tree will be on your right, and it parallels the power lines to the other side of the ridge.
Continue straight on the Bill & Marion Certain Trail along the east bluff. There will be a few more overlooks of Big Cove. One of these overlooks is near the second intersection with the West Bluff Trail
. After soaking in the view, continue south along the ridge until you reach the Varndoe Trail at the TV tower.
Typically, mountain bikers turn right on the Varndoe Trail to form a loop back to the trailhead, but the Bill & Marion Certain Trail actually continues a few more hundred feet and ends at the cell phone tower. Ironically, T-Mobile owns the tower but AT&T provides the land service to it. Do not go past this tower or you'll be on private property and subject to target practice.