there is a nice public (and reportedly bong-friendly) campground near Molly Stark state park in Marlboro VT, called Moss Hollow Campground (in case you can't get into Molly Stark), it's on Moss Hollow road whiche would be on a local map
I found a link with a map:
http://www.hikercentral.com/campgrounds/118334.html
also worth checking out nearby is the nearby public beach at Harriman resevoir (not for camping just to visit), take route 9 west 1-2 miles from Molly stark, turn Left on Route 100 South at intersection, go 3 miles or so, turn right when you see sign for Flames Stables and go to the end of that road there is a public beach with picnic area and BBQ pits as well as some trails, beware there is a nudist beach 1/2 mile north on one of the trails