By the way, don't dismiss visiting a glow worm cave or dell.. on the South Island I've been to the dell outside Hokitika, where you will only see them at night, so a reason to overnight nearby (my homestay host actually walked me over to the dell). https://hokitika.org/things-to-do-pt...m-dell-walk-2/

North Island has the most famous cave near Waitomo, which I visited on my first trip in 1988. But I believe there are others, e.g., https://www.newzealand.com/us/plan/b...low-worm-tour/

An out of the way spot to visit with unique scenery (Nikau Palms) on the South Island is the Karamea area, nearby the Oparara Arches and Scott's Beach Track, (south end of Heaphy Track ) However any visit to the remote ends of the West Coast needs to be researched as far as road conditions and services.

https://www.karameainfo.co.nz/