Heading due north to Roscoff ferry port this route is fantastic - twisty, wide and quiet roads.
From Plymouth out to the South Hams area, east of Plymouth, through to Avonwick and back down the A38 to Plymouth
From Cornish fishing village Looe to Plymouth via the Torpoint Ferry.
Loads of slowish corners through Dartmoor. Can sometimes have mud on road due to farm activity, but otherwise good.