NZ is high on my list of places to visit one of these days soon. That and Tassie. Most of my life I've been a solo traveler, but as I get older, I don't enjoy it as much, has to be the right kind of place/vibe, etc. Plus, I'm at that age where I'm spoiled and am not staying in hostels with 22 years olds, just, no. I need my own bathroom lol.
That said, any advice on parts of NZ that would be cool to check out as a solo traveler?
It's a cool place to visit
My recommendation is if you come in winter, then focus on the South Island - or if it's summer, then stay north.
Travelling is really easy, and you are never more than an hour from a beach no matter where you are in the country.
Solo travelling - up north is definitely the Bay of Islands (Paihia/Russell), sand dunes towards Cape Reinga. Matakana is all good too for a lazy wine trail. Rotorua (the stinky mud place) is incredible.
South Island, hit up Nelson, cruise (boat) the Marlborough Sounds and don't miss Queenstown.
Had some Australian friends do a trip last year, and I put together an itinerary for them. It's hard to beat local knowledge.
More than happy to do the same thing for you if you like.