Visit the cave paintings at Lascaux and elsewhere (although they don't let you see the real stuff in some places) as its genuinely fascinating with a good guide.
Walk around (but travel by bike or car) in the generally good weather and stay inside for the almost nightly thunderstorms. If possible have access to a pool as it can get quite hot. Villages such as Eymet are well worth walking around but avoid this and this general area if you're looking for (any) nightlife.
Quick Tips:
Visit the rivers, go canoeing, avoid the trail, find something to occupy you.Best Way To Get Around:
We drove there, and the place we were staying was fairly secluded so really a car would be a good idea. If you're fit you can probably get around quite a bit cycling, but otherwise you would have to look for large centres of population for anything else really.