The Dordogne, especially the Perigord Noir zone, is small enough that you might discover your favorite places just by driving around. If you have just a short time, a map and guide might help.
Guide Book for the Dordogne
When you arrive in the Perigord, look for a copy of The Paths of Prehistory in Perigord. It's a great introduction to the history of the region with great photos you won't be able to take, as well as some pretty nice maps. It's by Editions Ouest-France and the ISBN is 273732260x.
Indexed Information on the Dordogne and the Perigord Noir
See
Dordogne - Travel and Tourism for the Dordogne Region in France for information on visiting prehistoric sites (with opening times and locations), lodging, and general tourism information for the Dordogne.
Have fun on your Dordogne vacation!