Bob,
It just so happens that last weekend I was at our camp on Hancock Pond and I rode my Mountain bike north from Swamp Road to Sandy Creek on the roadbed on Saturday. You can access the ROW at Perley's Mills Rd. and you can drive all the way to Sandy Creek. The beaver dams have been removed and the roadbed was high and dry. I would suggest caution if you cross the Willette Brook bridge in a vehicle. It was built for logging trucks but it has been a few years so I would check it before crossing. On Sunday I went the other way and biked to Barker Pond. You can't cross the small bridge at the head of Barker Pond (at Twin Lakes Station) in anything larger than an ATV. The bridge is in shaky condition. The supports are fine but the wood is questionable. Otherwise, you can drive a vehicle (truck or jeep preferably) from the part of the West Shore Road (Hancock Pond access road) which runs through the Notch on the old ROW all the way to the Twin Lake Station site, where there is now room to turn a vehicle around. You can still see Joe Bennett's old cottage at Hancock Pond (it has a locomotive weather vane on top so it's easy to find and it is right next to the road). I hope this helps.