The road north to Waipu is straight forward. It's State Highway 1 all the way - no map reading skills necessary.
At Waipu, we turn left on to Shoemaker Rd and travel past cows grazing on the green hills undulating around us.
Enjoying the countryside, I can forsake my navigating task, taking an occasional glance at the map. When the less-than-impressed driver realises we're taking a wide detour, he growls, shakes his head and reclaims the map.
Our 5-year-old in the back seat is desperate for the map, she's sure she can navigate way better than either of us.
The last 5km of Waipu Caves Rd, windy and unsealed, is framed by mature native bush, in one section a stand of kauri towers above. At Waipu Caves Scenic Reserve we walk across a grass paddock to the base of a large rock face.
The cave's gaping entrance is generous, only those taller than 183cm (6ft) need bow their heads to safely enter.
Inside, within a few metres a small muddy track leads down to the cave floor, opening into a large limestone cavern.
We shuffle along cautiously as our eyes' adjust to the darkness, the natural light dimming behind. Between the three of us we share one narrow light beam from a small torch - and, considering our recent unnecessary detour, it's no surprise who's not holding the torch.
Soon we arrive at a large pool of water blocking our path, no way around it, Miss 5 is piggy-backed and we adults take off our footwear before edging our feet into the numbingly cold but clear water.
We wade through it stepping over a bed of smooth stones, the only sound is water as it sloshes about my knees. Then others approach from the opposite direction, their talk of bats and critters is unnerving - I step up my pace to reach dry land.
The air becomes warmer as the cave veers to the left and stalactites and stalagmites at varying stages of growth rise and fall around us.
The pointy end of one lit stalactite reveals its claim, a few strands of human hair extracted from someone's scalp. Directly above the ceiling is a night sky of twinkling stars - glow-worms. The torchlight reveals them dangling from their clever silken threads.
Shuffling along the passage between the icicle-shaped formations passing other trundling in the opposite direction we almost bump into a photographer's camera set on a tripod at the cave's end.
Below to the right a gap, waist high, leads into another space, but it can only be accessed by crawling though the water blocking its entrance.
We're not that keen and return the way we came.
Outside, next door in a tight crevice stands a stagnant family of cave wetas. Their shadows make these arthropods look doubly fearsome with twice as many legs.
Nearby we take a walk on a track that leads up into a mature native forest of taraire, kanuka and totara.
The walk continues for 2km but we don't make it that far, instead we settle down on one of the large scattered rocks covered in moss to eat our picnic lunch.
We soak up the old world feeling around us: karst limestone landscape, ancient caves, stones, moss and lose vines hanging randomly down from branches above where kereru hop from tree to tree.
NEED TO KNOW
• Waipu Caves is one of four karst limestone landscapes in the North Island.
• Check the weather, if it has been very wet access may be limited. Take a reliable torch.
• The caves visit is unguided, with free entry. No dogs without a permit.
• It is approximately two hours' drive from Auckland city to Waipu Caves. Take SH1 towards Whangarei, 16km after Brynderwyn, turn left on to Shoemaker Rd, in about 6.5km turn left on to Mountfield Rd. After 700m turn left on to Waipu Caves Rd, continue for another 5km to Waipu Cave Reserve.
• The caves are about a 20-minute drive from Waipu town.