Fletcher Bay & Port Jackson
From Coromandel there a couple of roads open to you if you want to cross the mountains. You can take the Coromandel-Whitiang Road, 48km on SH25, which takes you through the old gold town of Kuaotonu. This is the slow road to Whitianga and takes you up to 347m providing spectacular views of the Coromandel Harbour and Whangapoua Harbour which it bypasses.
Alternatively the direct Coromandel-Whitianga Road, 33km on Highway 309, offers a few sights and stops along the way. The road snakes through lush bush amidst scenic views of the Coromandel coast. This is also your gateway to climb Castle Rock, 525m/2km/1.5hr return, for some great views over Whangapoua peninsula and the Mercury Islands. 11km from Coromandel, you'll find the Waiau Falls where you can take a swim at the base of the falls. Next is a short walk to the Kauri Clump Scenic Reserve which is dedicated to the protection of the fine, kauri trees which dwarf the surrounding bush.
To get to Fletcher Bay and Port Jackson from Coromandel take Highway 18 on a scenic ride lined by brilliant red pohutukawa trees in summer and beautiful bays and beaches. Colville, is a tiny settlement which was the central area of the kauri-timber district. This little place, is importantly home to the last gas station and general store en route to the northern peninsula. Colville was once called Cabbage Bay, so named after Cook ordered all members of his crew prevent scurvy by eating the plentiful surrounding native cabbage trees.
The next leg of the trip is the scenic but unsealed road to Fletcher Bay. You'll pass Watcherman, Little and Great Barrier Islands before you come to Port Jackson, a lovely sandy beach next to a DOC camping ground (4$). The road gets even rougher from here onwards and can be subject to landslides from time to time, so you're best getting an update from the locals before you head off. Fletcher Bay, famous for wrecking ships lies 35km from Colville.
The Coromandel Walkway
This 14km/6hr return walk is worth the effort. Head to Fletcher beach for the beginning of the track. It's almost impossible to lose your way thanks to the DoC signs. The track itself takes you along the coast and hills dipping through bush and farmland. You'll pass some little bays and reach higher hilltop views of the Pacific Ocean and the coast before you return to the dense bush. At Poley Point, a short but steep climb, will get you to the estuary at Stony Bay which is good for swimming. If you're short of time or a wee bit pooped you can get a lift to Stony Bay and walk to Poley Bay which will take you through the most popular section of the walk. (10km/3hr).