I rarely found such a good website as the Baie de Somme website.
The site also offers free hikes and maps for download, but those are monolingual French. Not really a problem, while the maps are in universal language. Not all the maps are 100% clear, but they serve the purpose. The map and the hike of St-Valéry (fiche 22) is very good!
click here to choose a hike.
If you'd like some additional info on must sees in town or in the region, lodging and so on, don't come here on a Monday! Weekly closing day of the Tourist Office (visitors center).
Fondest memory: The office is located at the Place Guillaume le Conquérant. Very easy to find. It's location number 1 on this map. (scroll down to page two)