First, take a flight from SFO/LAX to Auckland NZ, then a connector to Wellington Intl. You'll be more than half the way there. Get used to driving on the other side of the road.
Ride or drive to the suburb of Karori; if you can find your way to the Beehive, at the end of Lambton Quay - then follow the overhead trolly bus wires above Bowen St - they lead all the way through Karori to Mud Cycles and South Karori Road (about 5km).
Head down South Karori Road for 1 km - you'll see the carpark and foot bridge on the right side of the road. Print yourself a copy of the tracks map (see above) before you go.
Carpark and picnic area
The main carpark and entrance to the park is 1km down South Karori Road. The easiest uphill ride is called the Koru and starts from here (see map above). It's always easy to end-up back at the carpark (via Lazy Fern, Live Wires or SWIGG / Starfish).
This is only a portion of the full trail network