This narrow section of road is the Old Highway West. It started life as a gravel road in the 1950s, was improved in the 1960s to enable road trains to travel this route, and then designated as National Highway in 1974 and was fully reconstructed and sealed to a good standard by the early 1990s. This newer section, which can be seen across from the Old Highway here, is a definite improvement for today's traffic needs.
The cache is a camouflaged metal drinking container, hidden among the rocks.
It contains log book, pencil and swaps. Plenty of room for TBs and swaps.
I have added a trailhead which is a gravel access road from the main highway on to this older section.
Happy hunting.