There is a lot to see in the area and probably even more to do. To get a good idea what to do and were to go, the tourist information office in Lalinde is a good start. They have all the right addresses, prices and time schedules. (They may very in low and high season). The tourist office is just over the bridge of Lalinde to the left, across boulangerie Ulrich.
Atractions and activities:http://www.northofthedordogne.com/dordogne-attractions.php
Castles & Chateaux: https://www.northofthedordogne.com/chateaux.php
Advice is too book the Lascaux caves near Montignac a couple of days ahead before going there. In high season they tend to sell out a couple of days in advance.