You might be a bit late for autumn in the high country by this time. I was in ChCh the other day, and there was deffinately a chill in the air, with fallen leaves blowing all around cathederal square; quite a nice sight. Here in Wanaka, about half the trees are turning, and some areas are already becoming barren, but a lot of green is still left.
Camper van is a good way to go. When out in the country side, there are many "rest" areas where you can pull over for the night. DOC camp sites are pretty sparse in some areas-none in Golden Bay or Nelson areas, some have showers, but are more expensive ($12 night).
For your time frame, I would say focus on one area, instead of trying to see everything. If you want mountains: head from ChCh past Mt. Cook to Wanaka, then Lake Wakatipu area. If you want relaxation (and no sandflies) head to Golden Bay and do some easy walks-drive the 45km of gravel rd to Paturau and walk along some amazing beaches (at lowtide).
Mackenzie country, March 19th
