We plan to spend two weeks next April in Bretagne. We will have a car and are more interested in the interior than the beaches. Our first few days will be in Rennes. Any recommendations for a small town or village for an extended stay?
April + interior Bretagne = high chance of rain. Be aware of it...and perhaps you'll get lucky.
Bretagne is a bit too large to be explored from a single base. Looking only at the interior, I am thinking about the following options:
Rochefort-en-Terre is reportedly (never been) a beautiful village (one of the "plus beaux villages de France" if I am not mistaken), and is quite close to Vannes, Golfe du Morbihan, Carnac, Guérande...
Josselin is as central as it gets and a very pleasant town with an impressive castle.
Further west, Huelgoat is in a very scenic part of the interior (forests, standing stones, lakes...), and gives access to the dramatic "Côte de Granit Rose" on the northern shore of Brittany and Crozon peninsula in the west, as well as to a string of villages with remarkable religious architecture (search for "enclos paroissiaux") such as Pleyben and Saint-Thégonnec.
Another idea would be Quimper, in the southwest, near the coast but not quite coastal. It is a larger town with a very attractive historical center and good access to many points of interest within 1 hour (Concarneau, Pont-l'Abbé, Pointe du Raz, Locronan...). In April, it would be much more lively than any of the options above.
I agree with balso about the rain. You need to check historical precipitation for your dates.
Three bases: the south around Vannes, the west in the Finistere, and the north Guingamp area.