Boulder Mountain Trail Professional Review and Guide
"This route, another side road to the Mount Antero Trail, is also rough and rocky but less so than the Mount Antero road. The challenge of this road is that it is narrow with very high drop-offs. To make matters more interesting, especially if you have a full-sized vehicle, small pine trees grow on the inside edge of the track, pushing you perilously close to the edge. If that is not enough, sections of the road are significantly off-camber!
Special Attractions: Challenging 4WD trail; Spectacular alpine views. High-clearance 4WDs are required. This trail has either a rough, rutted surface, rocks up to 9 inches, mud and deep sand that may be impassable for inexperienced drivers, or stream crossings up to 18 inches deep. Certain sections may be steep enough to cause traction problems, and you may encounter very narrow shelf roads with steep drop-offs and tight clearance between rocks or trees."