So the map I gave you link for is just technical half of the story on Mt. Holyoke- it is called and you access from "Batchelor Street" in Granby.

On Rte 116, you can park on The Notch and bike on the other side of the road on a system similar in length but mostly flowy stuff called Earl's Trails.

There are riders on both sides almost all the time so most likely you will bump into someone who can give you a tour.
have fun