We had a great stay with Kat and her husband. They gave us great advice on what to do in NZ. We only stayed one night, because we picked up a campervan the next day. They picked us up at the airport and brought us to the campervan company the next day for a small fee. Therefore I can't really say anything about public transportation, but for anyone who wants to stay just a night while waiting for a flight, that is perfect. They even had German bread :)
Kat and her husband were really nice and we really felt like guest and not like paying customers. Great.