The Long Mountain Trail at the Mount Holyoke Range State Park in Granby, MA, is a moderate 2 mile out-and-back hike from Mt Harris Rd up to the summit of Long Mountain.
Follow the M & M trail (white blazes) from the parking lot. The hike is uphill almost throughout the entire hike. Just before the last climb to the summit of Long Mountain, the trail climbs a steep set of stairs, which can be iced over during the winter or slippery after a rainfall, so watch your step.
The lookout is on the far end which leads on to the notch visitors center. The lookout is not cut out from the trees very well, so you get better views during the colder months when the leaves aren't on the trees.