The traditional Northern Circuit route has a 4th day — Whakapapa to Mangatepopo — which completes the full circuit of the volcano. Few hikers are doing that section any more, though the track has been improved in recent years.

One other interesting option would be exiting from Waihohonu hut to the desert road rather than to Whakapapa Village — saving you about 7km of walking. Consider this if you are short of time. You would need to make a special tranportation arrangement.