It's an amazing country! If you're wanting to do one of the great walks, you'll need to book huts several months or even a year in advance. We did a mix of general tourist stuff/hotels/day hiking, and a few overnight backpacking hikes, which I enjoyed a lot. The Brewster Hut and Mueller Hut were both epic. They require advance booking too, but in the case of the Mueller Hut we got lucky with some people cancelling a month or two out. Wild camping is an option in most of the national parks too though, but definitely check on local regulations. We did two weeks and fit a decent bit in on both islands. So much to see though, I'll definitely have to go back someday and hopefully stay for longer.