We didn't have a very good map for the Loire Valley - just a road map of France - but the directional signs in the area are actually very good and we were able to find our way without a problem to the chateau de Chenonceau. It was about a 40 minute drive. It's considered one of the more beautiful chateaux in the Loire. Apparently King Henri IV built it for his mistress Diane de Poitiers. At that time the portion over the water was only a bridge. When he died, his widow Catherine de Medici threw her out and later completed the structure over the bridge. (Needless to say, it was presumably the slaves and serfs who did the actual building in each case, not those people.) During World War I it was used as a hospital. During World War II the Cher river which passes under it was the southern boundary of the Nazi occupied territory of France, and many people were smuggled through the Chateau to freedom in the South.
It was surprisingly not that big. The area over the river is a single large room and the whole chateau can be toured in about 45 minutes.
One of the most interesting areas is the kitchens. Here is a rotisserie with a mechanical contraption attached to a weight outside, which pulls on the rope so it is not necessary for a person to constantly rotate the rotisserie.
Gardens are also beautiful and well maintained, and kids would enjoy the maze (with no wrong moves).