What to do, what to do...

Jose and I are going to spend our summer vacation with Jose's brother Sergio, who lives in Oviedo, and his wife and daughter, Ana and Iria. We all really like the idea of going camping together. The only problem is that we don't know where. Last year Jose and I camped for two weeks in the province of Cadiz (southern Spain), and we loved it. We were thinking about maybe the coast of France this year. Any ideas from savvy European campers would be great!