We have a place on Lake Winnisquam in Meredith. Our communnity is called Waldron Bay and IMO we have one of the nicest beaches around. I know perferred porperties has at least one house in the development the rent by the week (no this is not an add for my place, we don't rent.
www.steveweeks.com also has a lot of rentals in the area.
We have a 6,4, and 3 week old and love the area. Again IMO Winnisquam is a little less crowded if you want to rent a boat. I think you may find the rental prices a little better as well. What ever you choose, I am sure you will be back. Good Luck.