The Darent Valley path runs from Sevenoaks through Dartford to the banks of the Thames .The
Wealdway path runs from Eastbourne through Tonbridge to Gravesend. The Medway Valley path runs from Tonbridge through Aylesford to Rochester. Crossing these you have the North Downs Way / Pilgrims Way and the Greensand Way . Kent County council and East Sussex council produce great guides/maps for these paths.