A route less travelled in the rolling Hertfordshire countryside whose only real modern intrusion is the occasional hum of a plane overhead using Luton Airport. But who needs to ruin the climate when a swift train journey brings a glimpse of the late Queen Mum's ancestral home and George Bernard Shaw's rural bolthole, taking in clues to Harpenden's past and a rare chalk stream? Almost 500m elevation. A long walk at a reasonable pace.
Bring a packed lunch. Pub stop.
Travel: Take the 9:36 from London St Pancras, arr. Harpenden 10:01.
Meet outside the main exit off Platform 4. Easy Thameslink options from south of the river btw.