You can tent for free around Mangatepopo... just has to be 500m or more from the trail, i was camped out up there for about 4 days over the holidays getting some climbing in and found a pretty sweet campspot up on the ridge behind mangatepopo hut but a bit higher up... it meant a wee walk back to the the hut every now and then to steal their water but we had lots of bottles between us and only had to go back there once.