Just west of where Bull Pond Road meets 293, there's an access road on the south side (on West Point land) which appears to be built on the little bit of ROW that was graded: it is pointed at what appears to be a curving cut, now occupied by a stream, on the east approach to the tunnel. Collectively, they curve from SW at the Bull Pond Road junction to about NNE at the portal. It shows up nicely on high-resolution DEMs. I can't find any trace of a west portal.