In our case, we showed up at Montrésor on a quiet early summer afternoon. Nobody else was there. Warm welcome from the staff and when they saw we had an English cocker spaniel in tow, the welcome got even warmer! They are real dog lovers there and urged us to bring our cocker along on the tour. I think they were happier to show our dog around the chateau than us ;-) There is a big armoire type ornately carved door chest in one room that is actually a safe originally from Amboise or Blois (I don't have my detailed notes in front of me). It is full of secret compartments...they recently found another two hidden drawers. There is one room that you can see only with the guides, but it's kind of a surprise, so I won't go into detail.
This is one of the most fun chateaux to visit...not that big, full of interesting tidbits, wonderful tour guides, and a quiet but beautiful village. Some of our best photos were taken in Montrésor (village and chateau).
As we left, a tour bus from Poland arrived. As I noted earlier, this chateau is very popular with Polish visitors.
Our other most pleasant surprise in that part of the LV was Fougeres sur Bievre along the D52 halfway between Montrichard and Cheverny. The village recently got a large infusion of cash from the government and they've spent it well--the village has been carefully cleaned up and restored. They are also restoring the chateau and from time to time classes are offered in medieval crafts and trade techniques (woodcarving, working with willow, etc.). The chateau also has the most ornate chicken coop you'll ever see. Fancy chicken breeds strutting around their own mini-chateau. A real hoot.

Yes, Fougères is a great place -- the château is kind of a museum showing how medieval castles were built. The garden and "heirloom" chickens are fun too.