Thanks to everybody for your guidance. I did get to take a ride out of Tunbridge on Saturday afternoon (played hooky from the Jenny Brook bluegrass festival). The weather cooperated (cf. Sunday), and I rode a 23-mile loop through Tunbridge, Chelsea, Vershire, and Stafford, up in the hills. Climbed 1000' ENE up Stafford Road, well-paved, and turned N on County Turnpike (a.k.a., County Road), gravel and recently graded, rolling but with a net descent of 500', then picked up Jenkins Brook Road (Chelsea), heading SE.
Stopped at the corner of Jenkins Brook Road and Vershire Center Road for a little lunch, and struck up a long conversation with Bob, who has lived at that spot for 35 years. We discussed the fact that different maps often disagree about many of the roads there, and he allowed as how the track extending Jenkins Brook Road to Turnpike Road (Vershire) through the Chelsea Town Forest was passable: "My wife and I have walked it many times".
I thanked him and continued out Jenkins Brook Road, rougher and steeper now, climbing past the old buryng ground at the edge of the Chelsea Town Forest. After that, the road disappeared from some maps, and quickly showed its Class 4 colors. Riding activity alternated between picking a line and proceeding with caution, to dismounting and THEN picking a line. At some point along here, I hit the high point of the ride, 1771', and started a rough descent. For about a quarter mile, picking a line consisted of picking the next stepping stone, and trying to keep the bike in water shallow enough to not soak the bottom bracket: the roadbed was an active, flowing stream-bed, helping to water an extensive wetland. THIS WAS ALL BEAUTIFUL.
Eventually, conditions improved, and I was riding again, headed S on Taylor Valley Road, and descending. This was a beautiful gravel road, not as recently graded as County Turnpike, but ridable at speed, running alongside the West Branch of the Ompompanoosuc River, which was every bit as pretty and out-of-the-way as its name.
This descent ran about 800', and brought me to the Justin Morrill Memorial Highway in Stafford, well-graded gravel, where I turned NW and commenced a 600' climb. Along the way, gravel became pavement and the Justin Morrill Highway picked up the alias of Stafford Road. Admired the pastures and elegant horses at the top, to say nothing of the peaks of the Green Mountains rolling off to the West, then rolled down Stafford Road for a fast descent, topping out at 48.8 mph, if the little pocket devil that makes up numbers for me is to be believed. The good condition of the pavement was much appreciated just then, as were the stability of the LHT geometry and the Compass 26"x1.75" tires, which performed reliably in all conditions encountered.
This ride made me happy, and I'll come back when I can.
rod