Hi indie,
Last July/August I spent 5 weeks travelling around NZ on my own. I'm 54, never travelled alone before and thoroughly enjoyed it. I stayed in backpacker hostels, always asked for a single room and prices varied from $25 to $55 per night.
I did a Magic Bus tour, hired a car for a while and am going back for another 5 weeks this year!
I presume you have(or will buy) a good guide book. I prefer the "Rough Guide" but others swear by "Lonely Planet".
Look forward to it, get planning and fire away with the questions.