Unless there is some reason, the Burlington area would make a better home base and a day trip to Plattsburgh might make more sense.
In Burlington, you could rent bikes or bring rollerblades and go on the bike path along the lake and you could stop and swim at North Beach or to Oakledge Park to the south (free if travelling by bike)(cars are charged admission). In the south end, Petra Cliff is a place with a climbing wall.
If you go to Ben & Jerry's in Waterbury, go to Stowe(another 15-20 minutes farther) for the Alpine slide and Bungee trampoline( there may also have a climbing wall)-fyi--this is a bit pricey and drive up the toll road which takes you up the highest peak in Vermont, Mt Mansfield. Then, nearby, drive through Smugglers Notch Pass, a winding mountain pass with high granite walls flanking both side of the road, very beautiful. While in Waterbury, you may also want to visit the Green Mountain Coffee Roasters visitors center, Cold Hollow Cider Mill and the Alchemist a local brew pub.
Shelburne Museum in Shelburne, south of Burlington is not a typical museum, it attracts over 100,000 people a year( in a six month season) This has lots to offer 39 buildings, a circus barn, a railroad car, a paddle wheel steamboat, a round bam, a light house, an old stone 2 cell jail, a double covered bridge, a house furnished from the 50's, a New York City, Park Avenue apartment. See shelburnemuseum. org or look at the TA comment/ feedback; highly rated. There is so much to see that tickets are good for two days. This year there is an antique gun exhibit, a look at fashion, and creative use of paper and couple of other temporary exhibits as well.
A couple of other ideas, mountain biking and paintball. Let us know if you want further info.
Edited: 08 June 2011, 21:41