First off, I really appreciate all the excellent advice received here. It’s been very helpful. So after more discussions with the wife, I put together an alternate South Island itinerary for comparison purposes. As it turns out, we both ended up liking the South Island itinerary more than the North. So, we're going to the South Island instead!
We’ve settled on the following general itinerary. We’ll have a few days in QTN to give us our best shot at a clear weather window for a Milford Sound flight tour. Some things will be planned closer to the trip based on weather conditions.
Day 1: Arrive AKL 5AM. Fly to AKL-ZQN. Arrive ZQN 11AM. Get rental car. Leisure day in QTN. Overnight QTN
Day 2: Milford Sound Tour -- Fly/Cruise/Fly (4hr duration), weather dependent. Alternate: Coach tour to Milford -or- Te Anau / Fiordland -or- Jet Boating / Glenorchy drive / etc. Overnight QTN
Day 3: Day in QTN area doing some of the above activities. Overnight QTN
Day 4: Drive to Mt. Cook in AM. Hike Hooker Valley Track -or- glacier tour -or- scenic flight tour. Overnight Twizel and stargazing. We found a really cool property for the night (expensive but hopefully worth it).
Day 5: Drive to ZQN. ~2-3PM flight ZQN-AKL. Overnight AKL CBD
Day 6: Morning in Auckland. 3PM flight AKL-DOH
Anyway, we’re always open to suggestions, but I wanted to put this here so it can help fellow FTers.