So, it's going to happen today. I'm heading out for the Tongariro Alpine Crossing. I took the shuttle bus at 6:00, so we started our hike around 6:30.
It's a 20 km hike, 800 m elevation up. They rated it with 6-8 hours, but if you're in shape, you will be faster. The path is well trotten, and very well maintained.