The reason I stress travel time so much, is that you can never be sure when you'll get a bus. They are scheduled to run about every 20 minutes, and MK is a 10-15 minute ride from AKL.
But, if you show up at the bus stop, and just miss a MK bus, you're stuck for another 20 minutes waiting, and this is all assuming that the buses are on schedule (they usually are, but you just never know).
DW and I just find it easier, and less stressful to plan like we're going to miss a bus. If you get to the MK early, you'll have time to walk around and check some things out, or scope out a great seat for Spectro. We also like taking our time at meals and don't like to feel like we have to rush through to get to the next thing.