[1] The ramble starts from the Volks Electric Railway at Paston Place - the midpoint on the line. It was at this point that passengers would disembark to join the daddy longlegs, which started from the groyne to your left. Start off along this groyne. Cross the railway and immediately turn left along a concrete path.
Follow this path alongside the railway (and past Britain’s first urban naturist beach.- The naturists are, however hidden behind a stone barrier). to reach Black Rock station. After this, cross a car park, aim for Brighton Marina, passing under the road to the Marina and aiming to keep as near to the cliff as possible. Emerge on to a concrete walkway which goes to Rottingdean.
[2] Once on the undercliff walk it is impossible to get lost. Keep going straight ahead with the cliffs above you and the sea on the right. (Sometimes the first stretch is closed because of rock falls. There is a step free route through the marina, running mainly along the north edge of the boating area. Ask for directions)
On the first part of the way, views are obscured by the marina development. As far as Ovingdean there is a sea wall about a metre high to the right.This obscures the view for smaller wheelchair users. At low tide the concrete blocks that mark the route of the daddy longlegs railway can be seen.The daddy longlegs ran on twin tracks,18ft apart.
[3] On reaching Rottingdean, go up one of the ramps if you wish to visit the village. Avoid the first one on the left, it looks temptingly gentle, but only leads to the next ramp, which is at an awkward angle. The other ramps rise for about 10 metres at around 1 in 10. These lead to the centre of Rottingdean.
You can end your walk at Rottingdean or return to Brighton by retracing the route out. Alternatively, continue along the undercliff to Saltdean, a further kilometre, The route to Saltdean has some fine views. At the end, there is a small ramp, through a tunnel and then turn right, travelling about 100 metres at around 1 in 20, or attempt about 100 metres at something like 1 in 7. The first route brings comes out near Saltdean Lido (not accessible) near some reasonable car parking. The second comes out on the south side of the road, going past a café. Return the way you came. The route back to Rottingdean along the top of the cliffs is not recommended. There are some steep hills and you must go along the side of the road.
It is possible to take a cliff top route from Rottingdean back to Brighton. It is hilly and there are a number of stretches of up to 100 metres with a gradient of up to about one in 10. It has fine views, but you will be by the side of a main road. Follow the footpath west past the pub and then across the pub car park. From here you can pick up the paved footpath/cycle route, which is good tarmac or attempt the grass route by the edge of the (fenced) cliff, which is more scenic and a bit further from the road. The grass track varies between wide stretches of fairly smooth grass and narrow stretches where the path may be muddy. You may have to double back to the cycle route at some points. Both routes are obvious. When you are above the marina the cycle route descends steeply. You can follow this back to the marina and marine drive, but if you started from Paston Place you may prefer to remain at high level and go along Kings Cliff, which has a wide sea-side pavement. This road gradually descends to the pier. Cross Marine Drive to the Pier and then turn left to travel along the drive back to the start.