Up 1 to Karapiro, across the river, through Horahora, past the Karapiro dam, through the back of leamington, past mystery creek, past the airport, Into Hamilton, left onto Collins Rd. All the way out, past the temple, straight onto Koromatua Rd to the end. Turn right, throgh the Whatawhata chicane, into Ngaruawahia. Fuel up at the BP, then towards Waingaro, and up SH22 into Tuakau. From there, you could get straight onto SH1 via Pokeno, or stop by the track at Pukekohe, or try out Ridge road.
Google maps is your friend. They reckon it takes 5 hours. I reckon it takes about 3 at a reasonable pace
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