Once upon a time, your life would have been in real danger looking for this cache in it's current location. I remember well, this windy section of State Highway One, that was eventually bypassed by the new current straight section, around 30 years ago.
Nowadays, this short section is a sleepy side road, servicing only a couple of premises. You should be able to park quite easily near GZ without having to worry about too many vehicles whizzing past. That said, it is still a public road, so do keep watch and take care.