High Ledges Wildlife Sanctuary is located off of Patten Road (which is off of Route 2) in Shelburne Falls, MA. There are no signs for it on Rt 2, but there are some once you drive further down Patten Road, which turns into a dirt road close to the sanctuary. There is parking available as soon as you turn onto the sanctuary road, but if your car can handle going further along, a small parking lot closer to the entrance gate of the trails.
In my opinion, this is the best place for hiking in Western Mass. There's an easy hike to the lookout at the ledges, longer hikes around the Sanctuary in dense forest, with mostly mild, invigorating terrain (one fun but frightening exception being at the furthest point from the entrance, a steep rocky climb near the stream on the North Trail--you don't need to pass through there to get to the cache). The landscape is varied and interesting, and there's even a lookout tower at the end of a trail leading out of the sanctuary (you can see the fire tower trail on the map "related web page" links to, it's not on the official sanctuary map).
The cache was originally stocked with three copies of Dutch Barnard's book, "In a Wild Place: A Natural History of High Ledges," for borrowing by those interested in learning more about the Ledges. Maybe they'll show up again on a future find, but haven't seen them for a while.