Eastern Karadeniz — This region boasts astounding natural beauty, colorfully dressed Hemşin women, many Georgian ruins hidden in the mountains, and perhaps the world's most spectacularly situated monastery.
Central Karadeniz — Central Karadeniz is home to the Black Sea coast's largest city, Samsun, beautiful riverside Ottoman architecture in Amasya, and Hittite ruins galore.
Western Karadeniz — The western third of Turkey's Black Sea coast is its most remote and beautiful (having been spared the indignities of the coastal highway), home to the ancient fortified port city of Sinop, and the beautiful resort town of Amasra.
The 350 km road from Amasra to Sinop is beautiful and breathtaking as it winds it's way along the rugged coast. If you are depending on public transport, however, it is likely to take two days. Expect to spend a night in one of the small towns along the coast, such as Inebolu, as bus service is town-to-town, and you are likely to arrive at some town after the last dolmus has left. While the towns along the way are unspoilt and unpretentious, they are a bit run down. If you have your own car or motorcycle, you can do the journey in one day (start early).