This is a very special route. Starting at either the north or south terminus, the track winds through the NZ jungle-ish forest. Partly on ridgelines with occasional views over the countryside, occasionally following the river, some smoothly runable, some ladders and lots of roots. An uninturrupled length of trail. The north end is more heavily trafficked but the trail (with a backup nav) is well marked the whole way.
There should be a decent amount of water in many of the streams most of the year with the only exception being late summer.
NZ Doc Track info: https://www.doc.govt.nz/parks-and-recreation/places-to-go/bay-of-plenty/places/kaimai-mamaku-conservation-park/things-to-do/tracks/the-north-south-track/
