Karamea is the end-of-the-road settlement at the northern edge of the West Coast, backed by Kahurangi National Park and faced by the Tasman Sea. It is remote even by West Coast standards, which is exactly why it works: rainforest, limestone, river flats, wide beaches, and very little hurry.
The strongest draw is the Ōpārara Basin, where dark tannin water runs below huge limestone arches and cave systems. The other big name is the Heaphy Track, one of New Zealand's Great Walks, which reaches the coast north of town.
Karamea is a better base than a passing stop. Stay long enough to drive the slow road to Ōpārara, walk the coast at Kohaihai, and watch the river and estuary change with the tide. It rewards travellers who like quiet places with serious nature around them.