It starts along a country lane through the secluded Austin Lodge valley, climbing to the isolated settlement of Romney Street. It continues on an undulating section to a ridge with fine views of the Darent valley, from where you descend into Otford, passing its scale model of the Solar System. After lunch at The Bull (or picnic), the route to Shoreham is another climb to a ridge, of along the valley depending on time & weather. You can also return home from Otford. This walk has two hill climbs and will be at a brisk pace.
Get the 0955 Ashford train from London Victoria, changing at Bromley South 1011 (platform 4) for the 1023 Thameslink train (Platform 2) to Sevenoaks arriving 1041. This is a train from Blackfriars 0946. Buy a return to Shoreham, or Otford if planning a short day.