I stopped at the Ty Nadan camp site a few years ago which is near Quimperle. There were some great routes which led straight form the site and followed the woods along the valley (even a bit of ST).
They have a national cycle route which is marked by a red & white stripe painted on kerbs, trees and lamp posts and it goes through woods, villages, towns, farmers fields etc. You can just keep going and going. I found some amazing trails which led to broken stone bridges crossing streams past abandoned farm house which looked likes scenes painted by Monet… down into Quimperle, une cafe ole, follow your nose back. Fantastic.
Buy some maps though… got very lost at least once.