I would second the nod for Roellinger in Cancale. When I was there too many moons ago, there was a main place and then a second two story stone house a short distance away (in which we stayed). There was an onsite woman who was exceptionally helpful and it was nicely decorated and at the time very inexpensive. And, of course, it enabled us to eat in the wonderful restaurant. As for St. Malo, the ramparts are nice. From them, I took a photo of some topless sunbathers. I gave this to a single guy in my office. For whatever reason, his cat ate it. As for Mont St. Michel, wherever you stay, you might want to bring food with you. The food on the Mont is both mediocre and expensive given the captive audience nature of this otherwise beautiful spot.