That path is called the cinder trackCycle path/pavement to Hassocks. Down to the station, follow the footpath under station bridge to Clayton. Cross the playing field, up the hill to the Windmills. South Downs Way to the Beacon, cross the road, after about half a mile take a right across the fields, down into the valley. Follow the track up the hill, through one gate then right at the second, back down (steep hill). Follow the fence until the next gate, up the hill through the woods until you reach a crossroads on the footpath. Turn left takes you to Stanmer Park. PM me if you want a map ! Pubs en route - Friars Oak and the Hassocks.