This was our sixth cruise with Princess, and the experience was as usual: very good, but not quite excellent. I'll comment on the things that struck me as perhaps useful to others.
Embarcation and departure were a snap, aided by our platinum status. We had stayed at The Sebel in Auckland (recommended -- an easy walk to the pier if your suitcases have wheels).
We were in C103 (Caribe deck). This is at the bow and is actually a balcony at an ocean view rate -- the reason being that the balcony is locked for understandable reasons when the ship is underway. Since it is at the bow, the ship's movement is more noticeable, but that was fine with us. It also means rather long walks to get to the rest of the ship, but that is also fine with us -- one needs the exercise. I'd recommend the location, assuming the motion will not bother you.
We chose any time dining, which works well for us. The food was good. I usually order fish for the main course, and am usually somewhat disappointed. That's understandable -- fish is less forgiving in preparation, and it's hard to prepare well on the scale required. I'm always an optimist -- and am usually not as happy as I'd hoped to be. Mind you, the fish was OK -- but not great. The cold soups and pastas, on the other hand, are usually excellent.
The staff is uniformly pleasant (must be a challenge to be so cheerful so consistently).
C103 is at the bow, which means there is more motion. That was fine with us. It actually is a balcony cabin, though sold as ocean view since the balcony is supposed to be locked when the ship is underway. The steward opens it on request when in port. The cabin is quiet, given that there is little traffic, and a long walk to the dining rooms, but then the exercise is useful.
We almost always do it ourselves. In Tauranga, we rented a car and drove around Rotorua. Driving in NZ is easy, even if they do drive on left. Traffic is usually light, and the scenery great. If you rent a car from Hertz (which requires a cab ride to town), ask to return the car at the airport, which is closer to the ship. There is a fine walk along the shore in Rotorua that leads past a variety of geothermal features.
If you haven't been to Wellington before, you don't need a shore excursion. Take the bus into town and spend a happy day wandering about. The national museum is outstanding. The shopping is fine, and the town lovely. There is free wifi in the central business district.
We spent a lot of time in Christchurch pre-earthquake. It is now rather sad to visit. Much of the central city is still blocked off and the new construction doesn't look to be the equal of the old. That being said, the city is worth a visit to see both the damage and the recovery efforts. We took the bus into town available as you leave the ship. It's cheaper that the ship's offering.
Dunedin is a fine city to wander about. You can fill the day on your own without difficulty. Should you wish the famous train ride, try to reserve it yourself and save a fair amount over the ship's excursions. We contended ourselves with walking about the city. However there is good bus service to surrounding areas, so if you plan ahead you can arrive confident of where to go. There is free wifi in the CBD.
Melbourne is a great city. If you haven't been there before, there is more than enough in the city itself to fill the day. Buy a city transit pass when you exit the ship and explore. We recommend the city art gallery (free, and with free wifi). The aquarium is excellent, but expensive. If you want to explore, rent a car and head for the Yarra vineyards. The "Puffing Billy" steam engine takes more time to get to and come back from than you spend on it.
You'll start or end in Sydney. Make sure you have at least three days to enjoy the city. The shopping is fine, and there are lots of other things to do.
Buy a transit pass ($44 for a week, $22 for a day). It's good for ferries, trains, and buses. Take the ferry to Manly. If you like walking, this is the place to go. There are wonderful walks all around the harbor. I particularly recommend The Spit to Manly walk. Take a bus from Wynyard to The Spit (ask the bus driver if he goes there), then start the 9 kilometer walk. It is lovely. Another great walk is from Watson's Bay to Bondi. Take the ferry to Watson's Bay, they walk south along the cliffs as far as you are minded to. When you've had enough, walk inland a block or two and catch a bus. You can enjoy Bondi, or keep going on the bus back to the CBD.
The botanical garden is also a delight. It's free, with a profusion of unusual plants, lots of birds, and the dreaded flying foxes (big bats).