Mt. Jackson and Mt. Pierce Loop is an eight mile loop up two mountains with 360 degree views.
From I93 take exit 35 onto rt 3. Follow that until you get to a four way intersection. Take a right onto rt 302 and follow that until you see an AMC information building on the right. Drive past the parking lot about 500 feet and park on the left right after the lake.
From there take the Webster Jackson Trail for 2.5 miles until you reach the summit of Mt Jackson. Then follow the Webster Cliff trail for another 1.6 miles until you reach the Mitzpah Hut. This hut is closed in the winter but it is a great place to stop and eat lunch in the summer time. From the hut, continue on the Webster Cliff trail for another .8 miles to the summit of Mt Pierce.
Mt Pierce has fantastic views of Mt Eisenhower and Mt Washington. From Pierce, take the Crawford Path for 1.5 miles down. Gibbs falls should be on your right. This only adds on .1 miles to your hike and is well worth soaking your feet in the cold mountain water after a long hike. Follow back along the Crawford Path for another .3 until you reach the road. Turn left and walk the road back to your car. You'll see the AMC building when you exit the trail.
The trails them selves are pretty rocky and ascend and descend quite a bit so be prepared for some intermediate trails and burning calves.
There are a lot of other side trails on this hike so make sure you stop at the AMC Info Building and get a map so you don't get lost. They also sell snacks and have a bathroom.