Xoanon here, I'll be posting more info on these locations when I do a little digging :) Tehanu might be able to tell you what the 'Big Day Out' event is.

From: Marvin D

Last week in New Zealand we had the Big Day Out. I travelled to this from Wellington to Auckland (a 7 hour drive). On our way up I happened to stop into the army camp in Waioru to visit my Uncle there. Interestingly enough he told me that on the next day they were receiving some people for LOTR who were to fly around and scout possible filming locations in the Rangipo Desert.

The desert is a pretty desolate area and is not far from the speculated locations of Mt. Tongariro and Mt. Ngauruhoe (Mordor)