Bordeaux, a beautiful, medieval city has been magnificently restored and is 45 minutes, by car. Saint Emilion is a former ecclesiastical hill village and has a World Heritage designation and is 15 minutes from Lestage.
There are hundreds of wine chateaux, large and small, famous and unknown, where you can go for a tasting and buy your wine for dinner (always phone ahead - it is the custom).
There are literally hundreds of medieval hill villages in this area of France - from the Dordogne Valley to the Gers (Armagnac), to Cognac, to the beaches of Archachon and the huge sand dunes of Pyla.
Biarritz, Saint Jean de Luz and the Basque city of San Sebastian are 3 hours by car, or less by train from Castillon la Bataille.
Paris is 3 1/2 hours by TGV (Train Grande Vitesse).
But...you can also relax on the patio in the shade of the magnificent Thieul tree and enjoy your local wine with smoked duck breast, local cheeses, pates and foie gras.