I haven't explored every corner of the area, but I think its biggest advantage is that you don't need to plan every hour of your holiday. There are small villages, countryside roads, walking routes and historical places that you can discover at your own pace. I would probably start with the castles and sites connected with Richard the Lionheart, then leave some time for simply wandering around and stopping wherever something catches your eye. If you enjoy being outdoors, the surroundings are also good for easy walks and cycling. I came across this local tourism website while looking for ideas:
http://tourisme-nexon-chalusfr.com. It has information about places to visit and activities in the area, which is quite useful when you're trying to put together a realistic itinerary. Personally, I'd rather spend a few relaxed days exploring one region properly than rush between several famous French destinations.