If you plan to travel far afield from your “home base,” as we did from Bordeaux to Sarlat and again from Sarlat to Oradour, it is helpful to use Google Maps.com, Mappy.com, or Via Michelin.com, to plan your driving directions. We also found it more practical to do this before we left home, with our own computers and printers, because it's often difficult to find the English version of these sites using European computers in Internet cafes. Using your own printer also means you won't pay a fee for printing copies at a cafe.
When you get the directions, be sure to get them coming AND going. You may think it would be easy to re-trace your steps, but it is all but impossible to do so. For example, exit 16 might be easy to find on the way to Oradour but impossible to locate on the return trip.
I'm embarrassed to admit that I forgot this important point for the return trip from Oradour, and, had it not been for a Portuguese truck driver in an aires (the French rest stop with a service station and restaurant located every 20 kilometers or so along toll autoroutes) who spoke excellent English and knew how to read maps better than we did, we might still be driving around the Dordogne countryside.