I suggest that you get in touch with the tourist office in the region/town you intend to visit and ask for any information they have on accommodation. The headings 'gite' and 'meublé' (furnished accommodation) may help. Most tourist offices have web links and communicate in English if you get in touch with them. Alternatively look at gite/holiday home operators such as Brittany Ferries - you don't necessarily have to book the ferry with them, but the price doesn't come down much - and see what they can offer. The area you are looking at is really beautiful, but it's very popular with the French and other European nationals too, so book early!

We have a holiday accomodation in the area and we advertise on the site french connections.

Hope this will help