In the Middlebury area, I think River's Bend Campground would fit your requirements. You can check them out at http://www.riversbendcampground.com/
We have booked a week there in August. If you choose River's Bend, tell them Lynn recommended them to you. DAR State park is also close by and has open spaces but no hookups. There is also Kampersville at http://www.kampersville.com/
. I think their sites are smaller although I have never camped there (too close to home).
I have never camped in the Stowe area so I don't have any recommendations. Most of the state campgrounds are nice but none have any hookups.
I work in Middlebury and live in a nearby town so if I can help in any other way, please send me a pm or an email.