Your experience will be markedly better than any bus experience in the US. Buses and drivers are clean, polite, and want to share their knowledge and hospitality Already mentioned that there will be stops and points of interest pointed out
It's a few years ago, but our favorite NZ intercity bus experience was Franz Josef to Queenstown on Christmas eve. Two people who had purchased tickets were not on the bus. The driver asked the passengers if they minded if he did a loop around town. .franz josef is not very big to see if we could find the passengers since the would not be a bus for the next few days. In short order he found the passengers who needless to say we're very appreciative.
Enjoy the ride