We will be in Ludlow for a week, mid August and don't mind traveling an hour to fun destinations.
Okemo Mountain in Ludlow has a mountain coaster which looks really fun.
Take a hike to the Ice Caves and White Rocks in Wallingford (get trailhead off Route 103 to the west of Ludlow)
Montshire Museum in Norwich is fun though may be a little young for the 16 year old. If you go here you can also visit King Arthur Flour (if there are any bakers in your family) just south of the museum on Route 5. You can also go across the river and visit Dartmouth College, less than a mile away.
Ditto Buttermilk Falls.Edited: 4:36 pm, June 12, 2017
Great info here already. I will add a little based on my experiences. You can actually walk to the bottom of Quechee Gorge and swim in the Gorge. Kids will love this. Hiking trails also in the area.
I will also add a few "rainy" day activities :) just in case...
In Weston is the Vermont Country Store. Something really everyone can enjoy.
Camp Plymouth State park is an excellent park on Echo Lake with kayak, canoe, and paddle boat rentals, a small beach, volleyball nets and charcoal grills. The facilities are very clean and it is, one of the best parks, IMHO, in the VT park system.