Marton Park
To find this cache you need to have completed the Adventure Lab called Ramblin' in the Rangitikei. Each journal you get will reveal a number for the final coordinates.
Link to Adventure Lab: https://adventurelab.page.link/ZU4S
The cache can be found at S40 03.ABC E175 22.DEF.
Please be careful with the cache and make sure to replace as found.