Stage 1 is at the listed coordinates and holds a wooden puzzle box that you need to open. Please handle it carefully and keep it dry! (If it's raining it may be a good idea to take a rain check.) Please don't use force, it comes apart quite easily once you have figured out its secret. 
The co-ordinates for stage 2 are contained in the puzzle box.
It's safer to park on Sea Cottage Dr than on Ou Kaapse Weg. From the parking at Sea Cottage (PK - additional waypoints) head up along the boundary fence, to the Trail-head (T1), where you turn left. The route then takes you between Dassenberg 1 & 2 and through Secret Valley. These 3 caches can be done in conjunction with this one. The Secret Valley is a lovely, picturesque spot which contains a small pond after the rains.
At the end of Secret Valley take the path to the right and up over a saddle that passes between two small ridges (W1). Follow the path to the junction point (W2) where you turn left. At the end of this path, pass to the left of a small rock plateau, and climb on top of it (W3). At this point DON'T go straight to stage 1, as this will involve bush-whacking and a rock scramble up the ridge. Instead turn right (the path is a bit indistinct for a few meters, but soon becomes clearer) and head to the last waypoint (W4). As you approach the last waypoint look out for a path/gap to the left, between the rocks, where you can ascend the ridge fairly easily.
There are ticks on route, so check yourself carefully!
PS: I forgot to mention that when you get the puzzle box open, you're not finished puzzling yet!