Back in 97, we did a 3 week in depth coach tour of NZ North and South Islands with Guthrey Pacific Coach Tours, not sure if they still exist. It was leisurely with some 2 and 3 night stops, but missed nothing, saw and did everything, good hotels, meals, all inclusive, even the inter island ferry with the coach on board too, lol So I highly recommend a coach tour of NZ on a ship visit you only have limited time and range, done that too.