Navigation is a key skill of a brevet - a challenge not to be underestimated (particularly in the dark, at the end of a long day). The cue sheets that have just been posted are intended to be used with a selection of topomaps and guidebook directions. The altitude graphs are also handy for planning each day.
You can use a GPS, but don't rely on it 100% - take a couple of maps and the cue sheets, too. I recommend making some notes on the cue sheets, chopping them up into sections and then getting them laminated.
Here's what I recommend you take in the way of Topo maps:
1 - Topo250 map 19
2 - Topo50 map BV23 Virginia
3 - Topo50 map BW22 Oxford
4 - Topo250 map 23 (top third only)
5 - Topo250 map 17
6 - Topo50 map BT21 Waiuta
7 - Topo250 map 18
8 - Topo250 map 13 (bottom half only)
We've also suggested taking some directions from Classic NZ Mountain Bikes Rides (7th or 8th edition). These are all written for travel in the reverse direction of the 2012 Kiwi Brevet, but still contain some very useful information about level of difficulty, huts and directions to or from the trailhead.