Imma go out on a limb here and say that Waredaca is the nicest brewery in terms of environment/atmosphere that I've ever been to. It reminded me of more of a vineyard than a brewery. The kid friendliness was perfect, weather was gorgeous, beer was average at best out of the seven I tried. Peach Gose was delicious and would drink again, Coffee Stout was great as well... everything else was slightly better than a drain pour. Would return again.
Why is it going out on a limb? What other impressive breweries have you been to? Have you been to Manor Hill yet?
Kloster Andechs in Germany was one of my favorites. I'm not sure it was our five year olds' favorite, as it was a 6K round trip hike to get there. To watch her parents drink the best dopplebock in the world. (and partake in the festive beergarden atmosphere and food menu).
Now 9, She really did enjoy the Grand Teton Brewing Company, which we hit twice on our most recent vacation. Lot of kids, dog, even some people arriving by horse. Big outdoor lawn with this view (unfortunately no view of the actual Grand Tetons):
New Glarus was also pretty excellent to visit. But I went there by myself.