I'm very familiar with Brittany, and with cycling in Brittany. Get a Michelin map for the Morbihan département. Morbihan means "little sea" in Breton, by the way. Amaze your new friends with that little tidbit.

Anyways, get the map, and just go explore on the roads that are either white or yellow on the map. Most roads are white or yellow. The red ones are busier, and the double red and blue ones are like interstates.

Do you speak any French? If not, PLEASE, PLEASE, PLEASE take the time to learn the very basic of basics. Do not assume that people will speak English. You have time to learn the basic 10 words and phrases. If I did it in Greek, you can do it in French. No excuses here.

Other than that, have a great time and eat lots of galettes (savory crêpes made with buckwheat flour) and crêpes (dessert crêpes made from white flour) and drink lots of cidre. When you order cidre, order a pichet or a demi-pichet instead of individual glasses. It's strong, so be ready.

Bon voyage!