It's a gravel road through here. I recall once being a spectator as a car rally went through - - - there was lots of dust and small stones as you can imagine. Please don't try to emulate rally drivers, the smooth surface of the road relies on people driving in a more controlled fashion, particularly around corners.
Anyways, the cache. As this is a multi there is nothing hidden at the published coordinates. Take a look at the sign and in particular, the height above sea level. Call this ABC metres. The cache is hidden under a rock at
S 41° 14.424′ E 172° 55.B4A′
When hidden the cache contained a pencil but its always good policy to carry a pen or pencil just in case.