Just north of Waiwera is Picturesque Wenderholm Reserve. Offering such features as kayaking and boating, swimming, picnic and sporting areas, and not the least bush and beach walks. On your left as you enter the reserve is the boat ramp. The river offers excellent kayaking. Kayaks may be hired from Puhoi River Canoe Hire  but please book first.
The Pohutukawa shaded grass areas provide for perfect picnic spots as do the open areas for ball sport or throwing a Frisbee around. In the peak summer season barbecue areas can be pre booked through the ARC.  While there, visit  the original homestead,  (Couldrey House) which now houses a museum. Back toward the hill lies a walking track to Waiwera. At the base is a signpost with estimated times for the sections of the walk. The walk leads uphill through native bush.
Outstanding view can be had of the park and beach on the left.Continuing up further a wooden barrier protects an old concrete water tank set into the dry creek bed. This  would have been for the old homestead, possibly as a supply of water for the house and sheds. Think how tough those days must have been. Back to the present and we are now  walking up a staircase put there to protect the surrounds. It is a little steep but lots of rest areas prevail and glimpses of views make up for it. After the stairs the track levels a little. While the track is well formed it would be slippery after rain. Continue walking and resting through the native Nikau palms. The lookout comes soon enough. Fantastic sea views abound. They cover from Kawau Island around to the Whangaparaoa Peninsula. This is a good place to pull out the choc bars, but don't drop the wrappers. Once you are ready, continue down towards Waiwera. This part is a bit steeper and the track is not as easy as the uphill part. Just watch the roots and steps and all all be fine.  A few glimpses of Waiwera are to be had on the way down. At the bottom there is a choice between going back via the bridge and park entrance or around the beachfront. If going by the beach, make sure the tide is on the way out as the cliffs are too steep to scramble up. Walking along the beach is actually rock-hopping but the stones and boulders are not sharp. Don't be tempted to swim in the river as the currents are fast and unpredictable.
Save the swim till you get back to Wenderholm. It will be a lot nicer. Walk past the island and the rock pillars. A good place to ponder how the hill was formed. Being sand stone, floods have washed sediments down over the millions of years. Layers have hardened and then another lot washes down on top to dry and set also.

Now you just keep walking around the next corner or so and Wenderholm comes back into view.