There's a bit of bush to explore around here and you can drive much of it with an ordinary 2WD vehicle. But of course you can also park at the edge of the (sealed) Mt. Hay Road and stroll around these fire trails on foot. Your starting place on Mt. Hay Road won't be far from the Great Western Highway. This one is geo-family-friendly with no cliffs or sharp drops anywhere near GZ.
The cache itself shouldn't be hard to find. Check the hint if you have worries.
On weekends you may hear the distant firing from a rifle range to the south. However, you won't be in any danger around here.
(Depending on your experience in driving on less-than-perfect fire trails, you may want to park alongside Mt. Hay Road and walk the short distance up the side trail to GZ.)
Congrats to ASO for the FTF!