Rennes to St Malo - local train?

http://www.tripadvisor.com/ShowTopic-g187198-i1364-k1973081-Nantes_to_Rennes-Nantes_Pays_de_la_Loire.html

146 miles from Nantes to St Malo, or 2 days worth of cycling I'd guess. How about we get the train from Nantes to Rennes and then local train or cycle distance from Rennes to St Malo?

Cheers,

Mike