I can't express how much I love this place. To me, it's the perfect summer vacation spot for large extended families and friends--especially if you have children. The beach is easy to get to, and there aren't dangerous, steep stairs to navigate to get to the beach. The cabins and lodge are all rustic so you don't have to demand that children be super careful with all their surroundings--for example there's very little carpeting etc.
I personally love the historic charm of the place--it really feels like you've gone back in time. The screened in porches in the dinning hall and the boat house have great views of the water. The little cabins are super charming and fun to stay in. The dining hall is nice because you can seat such a large group of people together. Long lake is perfect for boating especially since there are cute little islands that you can explore. Another aspect that is nice about this place is the way it is surrounded by tall trees, so you are always in a cool breeze rather than baking in the sun--unless you want to go down by the water. There is also a nearby park that you can walk to which is great for a daily hike.
Because this place is so large, it is perfect for a big group. If I had the opportunity, I would return here every year with my family because I love the experience so much. The only critique that I can write is that the place is a little rustic, so renters should not expect the most updated decor or amenities (although there are new bathrooms, one new kitchen, and new washer, dryer etc.). But to me, this just adds to the historic charm. I wouldn't want it any other way.