Since my previous posting, I have finished exploring the trail and highly recommend it as a place to ride. On a hot July day, the temperature was very cool under the canopy of trees along the trail. If you like, you could lock your bike at the rack by Valley Falls Park in Vernon, and walk down the hiking trail to the pond and pay $1 to swim.
From the Colonial Road trailhead in Manchester to Kings Road in Columbia, the trail is 19.3 miles. I measured 900 ft. of climbing with my GPS. The last seven miles back to Manchester is almost entirely downhill. The most polished sections start from the Manchester-Vernon town line extending to Burnap Brook Road in Andover.
If you want a 30 mile ride on a stone dust surface that you could do on a road bike, go from Manchester and loop up and back on the Rockville spur and turn around at Burnap Brook. This loop will give you 850 ft. of climbing. From Burnap Brook to Kings Road is a hard packed surface with some loose stone that is best negotiated with a mountain bike. The 1.2 mile stretch from Parker Bridge Road to a wooden bridge over the Hop River is the only stone dust surface east of Burnap Brook Road. The last mile into Willimantic from Kings Road is a mess involving a bypass around the bridge over the Hop River that is tilting sideways. Past the bypass is loose sand, trap rock, and even railroad tracks. The bridge across the Willimantic River has rotting timbers and across the bridge the tracks are active. Turn around at Kings Road. Even better, turn around at the Hop River wooden bridge at 16.4 miles.
With regard to my previous posting and the crossing at Rt. 316, there is a safer and easier way than walking down the steep embankment next to the bridge abutment. Just past the traffic light in Andover (when heading east), look for a narrow path on the right out to Center Street. Follow Center Street to Rt. 316. Left on Rt. 316, then right on Monument Lane. Turn right into the museum driveway, and left to resume the trail.

The trail is hard packed stone dust from the Manchester-Vernon line to Burnap Brook Road in Andover, and could be ridden with a road bike. East of this point, the trail is hard packed dirt with loose stones that is best ridden with a mountain bike with suspension, although a hybrid without suspension (as I was riding) could make it though, but with a bumpy ride. With regard to the crossing of Rt. 316, there is a two-foot wide path on the left side of the abutment that users presumably created. Walk your bike down to Rt. 316 (Hebron Rd.) Turn left on Rt. 316, then immediate right on Monument Lane. Right into the Museum of Andover History driveway, then left onto the trail. The tunnel under Rt. 6 had only one working light and some broken glass, so ride with care. I brought this to the state's attention to fix the problem. This is a fabulous rail trail through wooded areas and is not heavily used. I plan to ride the easternmost part of the trail in the near future.

There is now a parking area for this trail at the corner of Parker St. & Colonial Road in Manchester. The trail is accessible all the way to this parking lot, which is south of where the current trail map shows the trail ends. The area below Taylor Street in Vernon south to the Manchester parking lot is not as cleared or as wide as the rest of this rail but it easily traversed by any type of bicycle and completely free of any obstructions. This Manchester trail head is more convenient to cyclists who are heading to this trail from west of the Connecticut River as it is easier to get to than the Church Street parking lot in Vernon. Also because there is no parking lots between the Manchester Trail Head and the Church Street lot, this part of the trail is virtually unused. In fact I started in Manchester at 5:30 on a Friday night and did not encounter another person until I reached the Church Street lot. To get to this new trail head in Manchester from Hartford & points west, take I-84 East to Exit 63. Stay in the left lane as you exit, and make a left turn on Tolland Tpke. Make a right at the first traffic light, Parker Street, and follow Parker for about a mile to the intersection of Colonial Road which hits Parker Street from the left. You will see the parking lot and trail head at this intersection.