Dinan would be my choice, even if you needed to stop and clear customs at Dinard first.
Its truely a wonderful little place,and the walk to the town is equally stunning. Dont expect a great deal of english to be heard on the radio, last time we were there the locals were most bemused by a G-reg turning up ... .although to be fair that was a few years ago now .
J'estime votre terrain verticale at temp trente et une etc etc, the only problem is when they reply to you hehehehe