Kent County Council has signposted a 19 miles walking route http://www.kentdowns.org.uk/40-places/the-darent-valley along the Darent between the Greensand Hills above Sevenoaks and the Thames http://www.kent.gov.uk/leisure-and-community/parks-and-outdoor-activities/find-a-walk/darent-valley-path and named it The Darent Valley Path.