There's a creek running down this edge of the Scarp Park that still had some water running at the time of placement, and is quite a torrent in the wet months.
You can make this a quickish find by parking at the end of Nangana Way (which doesn't come off Kalamunda Road, regardless of what Google and Garmin tell you! You'll need to go along West Terrace and in the other end of Nangana. Taylor Road also doesn't join up, check it out in StreetView!)
For a more interesting approach, start at the top at the end of Dorrington Road and come down a steep track and along the creek. Detour to the cache, then go back and continue along that track, switchbacking up until you're approaching Barron Road, then taking the path to the left that leads you back to your starting point. There's some great views over the North of the city plains from here, but take a hiking pole as the ascent has stretches of the typical "Scarp skating rink" pea gravel with honkey nuts!
The cache itself is an ammo can in a pile of rocks, at the base of the larger outcrop. The "decoy pile" you might find is quite natural, and it made us wonder if we'd been beaten to the spot when we saw it!