You will love it in the summer. Just remember that from the end of July to Labor Day weekend is the Saratoga Racing Season so if you can get a reservation, you may want to visit the track for a day.
We took our family there for Thanksgiving for about four years in a row up until last year. They are great with kids. There is a ton for kids to do. Everything from a rock wall in a gym to miniature golf on site. They schedule horseback riding trips and boat trips on the lake. The food is outstanding but pricey. We have stayed in the Lodge Suites and in the main hotel building. We always liked the main building the best but that was in the cold weather so we didn't have to go outside to get to the pool or the restaurants (which are in the main building).
HBC