There are lots of local walks in the national park and along the coast.
Ordnance survey maps and some good walking guides are available from the Maison de la Presse in the market square in Isigny sur Mer. The Madame who runs the Maison de la Presse is very helpful. The shop itself is part news agents, part book shop, part tourist and souvenir shop. English papers can be purchased and they also provide an internet service.
A highly recommended poket books with 30 local books is called:
"Les Plus Belles Balades des Marais du Contentin et du Bessin".
This is usually available from either the Maison de Presse or alternatively the tourist office in Isigny sur Mer can provide various walking guides.
There is a walk that start directly outside the Chateau gates with the option of a 3km circuit or a 7km circuit. The 3km circuit will take you out on to the local marshes and bring you back along the the River L'Elle. It is a pretty walk with an abundance of wildlife, particularly bird life to be spotted on the way. There is an information board and map of the walk outside the Chateau gates and there are information boards throughout the walk.
the 7km circuit follows part of the 3km circuit but then extends to take in the village of Neuilly la Foret and the hamlet of St Lambert before bringing you back to Chateau Neuilly.