Luggage and bags:
As this was part of a day trip from Christchurch to Hokitika, Punakaiki did not require any baggage. If this is part of a longer camper van, then this trip would be wisely put into a backpacker form.
Clothing/Shoes/Weather Gear: During August, the weather was definitely cold enough to warrant a fleece coat, and long pants. I was not cold enough to use thermal underwear, however Sarah was ready for a nice warm fire by the end of the evening.
Toiletries and Medical Supplies: Readily available in Punakaiki, but not in the smaller towns on the way.
Miscellaneous: I had to include this picture of Sarah in her Punakaiki Gallery Hat. I would assume that later in the winter this would be useful, however in August it would be overkill.
Clothing/Shoes/Weather Gear: It seems like this area of New Zealand rains quite a bit. When I was there, it was drizzling. So Jac & I stopped by the Tourist Centre to pick up some souvenirs (In actual fact to steer clear for the rain). The lady at the counter advised me to buy a beanie to keep ourselves warm, and that was what I did.