stowe is resorty. not far from the big city of burlington.
lots of great cycling nearby. probably deals to be had in the ski off season on lodging.
hiking, the stowe river path, new england cutesy town with touristy stuff. summer stuff at the ski hill. most hotels have pools.

heading south out of stowe you get into the mad river valley - waterbury (ben & jerry's tour) at the north end then down to waitsfield and warren. prime cycling - mountains if you want em on either side of you. 30-40 minutes from burlington for 'big' city stuff. lake, beaches, echo kids science museum, teddy bear factory, shelburne farms, etc. etc. bike path along lake, canoe, kayak, bike, rollerblade, shopping and eating on church st., etc. etc.

islands - as noted kind of neat - i ride up there from btv each summer - but flat for vt and pretty isolated. if you plan on parking and just hanging out a b&b or campground up there would be fine - but you're further from the mountains and burlington for the family stuff, but right on the lake.

if i didn't live here i'd stay out near waterbury / richmond area. ride in the morning climbing all sorts of hills or gaps (rt. 100 through the gulf, or over app, or on some dirt), then head into town with the fam, or to stowe for touristy mountainy type stuff. or send the fam into town and meet them later...