Start: Montreuil-sur-Ille

There is about one train per hour from Rennes to Montreuil-sur-Ille, the ride takes 15 minutes and costs about 6 euros, bikes are allowed on the train (at no additional charge, I believe).

It is also possible to start directly from Rennes by following the Ille river until Montreuil. Add about 20km.

Lunch stop: Dinan

Around km 50, stop at the medieval town of Dinan. Lunch. Visit.

Arrival: Saint-Malo

Depending on the energies left, there is the possibility to follow the shores of the Bassin de Rance along the GR34C. Add about 10km.

The bridge from Dinard to Saint-Malo passes over the Barrage de la Rance, where EDF has installed the famous "usine maremotrice". Nice views over Saint-Malo, Dinard and the Channel.

Another possible deviation is through Dinard. Nice villas by the seaside and the classic Promenade du Clair de Lune.

Stop at the hotel, shower, then enjoy Saint-Malo intramuros at night.