From the source of the River Cray at Orpington Priory Garden ponds the route attempts to follow the River Cray to the confluence with the River Darent (at Dartford Creek) and finally finishing as it joins the Thames. Start at metal gate between ponds in Orpington and finishing at a information board on the side of the Thames (past the barrier).
Route is mainly on roads/gravel tracks with short sections of mud (mainly through Foots Cray meadows). Road shoes probably recommended.
The Cray Riverway is a recognised route with various different start and finish points. It is logical for this FKT to start at source and finish as it reaches the Thames.