Greer asked me about how to ride through the Hunuas (just south of Auckland) so this is a quick list of routes that I've taken.
The Tour Aotearoa Route
As far as I know, this is the official Tour Aotearoa route. Coming from Ardmore, the roads are quite scenic but very steep at times.
The Straight Through Route
Starting a the Papakura Railway Station, this just follows the main highway. It's fine, but has the most traffic (although is varies depending on the time of day). When I rode up that first big hill on a Saturday morning, there were a fair number of big trucks going up to the quarry whose company I did not enjoy.
The Ponga Road Route
My preferred way. Starting at the Papakura station it takes Ponga Road instead of the main highway at the beginning. It's a bit longer and steeper, but much quieter.
The Half Hunua Traverse Loop
Rode this as a loop from the Pakuranga station. Lots of climbing (and decending) but also nice scenery. The last bit on the highway back to Papakura can have too many cars on, but is over fairly quickly.
The Half Hunua Traverse to Kaiaua
Enough climbing to be a real challenge, but nice scenery and the bit where you emerge from the hills and first see the sea is really nice.
The Awful Loop
As documented in a post of it's own. Very challenging (because you have to carry your bike for several kilometres) and not at all recommended.