It looks a beautiful place but I take your point about the length of the journey! It's quicker to fly back to the uk with transfers both ends included!
Josselin is about 3.5 hours from Tours by car and autoroute. It's not exactly on a main SNCF line. Not too many Tours to Josselin commuters, I'd guess.
my grand parents lived thereit's the sit of the *Rohan familyfamous in Britanny for its 8th of september pilgrimage to Notre Dame du Roncieryours