The CBST isn't a trail just yet, but instead a work in progress. Volunteer groups and VDOT are actively working towards completion of the trail. Portions of it are very well maintained railroad beds that have seen horse and bike usage for some time. This is your best bet as it is public land and generally safe to use along the maintained sections. Facilities and parking are limited and any use needs to be sensitive to neighboring residents.
Right now, the best section for a ride is from the Forest Service Mill Creek Road (off Rt. 615 east of New Castle) and then following the rail bed northeast toward Oriskany. The railroad bed has been stabilized and maintained all the way out to the #92 bridge about 5 miles NE of Oriskany. A round trip ride from Mill Creek to the 92 bridge and back is about 24 miles. There are many options for shorter rides along this section. A lot of adjacent land along this section is National Forest. Please note, there is about 3 miles, from Oriskany out to the end of Route 817, where "the trail" shares Route 817 with motor vehicles. Traffic on this gravel road is minimal, 14 - 40 cars a day by VDOT count. Parking at Mill Creek road is very limited, maybe 3 or 4 cars.