I have flat surfaces that need some character and I’m using 50mm thick polystyrene off cuts of flooring insulation that are glued down with exterior PVA to create it.
The outline of the access path to Platform one and road to the terrace railway cottages were drawn in with a permanent marker pen after studying many photos and determining a plan view. Then using a small flexible handsaw and a Surform rasp these are then carved out and shaped to simulate the embankments and general sloping terrain towards the A684 road below at the Garsdale Station South end approach.

Modelling has taken a little time and care (about three days so far) to ensure the cottages and bridge blend into the terrain before applying the road and access path surfaces and of course grass.
I am preparing module one for further detailing such as out buildings and dry stone walls so to get a handle on how the rest of the diorama will work with the next baseboard that will have the station waiting rooms and signal box.