$52 per day for a Nissan Wagon is very good if it's a 4WD. All fullsize 4WD's are a lot more expensive than the smaller things. I like the idea of the Outback if there's only one or 2 people, as it's more than capable but cheaper than the big 4WD's.
I sent this in a message to Knut: What I found with the US trips is that there are online booking sites that buy a large amount of business and sell it off cheaper than going direct. The first time I went with http://carrentalrepublic.com/
and the second time I went with http://www.netflights.com/
and for both bookings I chose to rent the car from Thrifty in LA. It's sometimes less than half the price of dealing direct with Thrifty.
I haven't booked a car for NZ yet. But I looked thru the above sites, and found a cheaper price with http://www.omegarentalcars.com/
so if I do book one I'll probably look to them. But I'd be happy renting from one of those "rentawreck" mobs too.
Hey with your boxes, remember that they do have to be pretty strong. You want to be able to perch the box on the crossbar of a trolley when it's fully packed, without it bending under its own weight. And imagine someone dropping another heavy box onto it or stepping on it (these things do happen unfortunately) ... yours needs to be rigid enough not to squash. I wasn't happy with the strength of single layer 5mm coreflute so I put a second layer inside, cross-grain. It sticks brilliantly with 3m77. The one I made for the April trip is still intact after months of storage. My long USA box which was 2.1m long and held 32kg needed 5mm for the entire inside layer and weighed 7.3kg. But the new shorter box for NZ which is 1.7m long and will only hold 23kg uses some 5mm and some 3mm coreflute inside, and it weighs 4.2kg.