Absolutely, let's break it down:

Best Time to Visit:
The best periods to visit Amasra, Safranbolu, Inebolu and Sinop region in northern Turkey are from late April to June and from September to early November when the weather is usually mild and sunny.

Route and Accessibility:
The main way to travel to these cities is by road. Buses and minibuses operate daily from Istanbul. Another way is by domestic flight, there are daily flights from Istanbul to Sinop. You can rent a car from Sinop to visit the rest of these places.

Altitude and Acclimatization:
The towns of Amasra, Safranbolu, Inebolu and Sinop are all at sea level or at low altitudes, so there's no need to worry about acclimatization.

Accommodation and Booking:
There are numerous hotels and guesthouses in these cities. But during high season the towns can get really crowded, so it is advisable to book your stay in advance.

Clothing and Essentials:
If you visit these towns in the summer season pack light clothes, comfortable walking shoes, a hat, sunglasses and high factor sunscreen. In winter, warm clothes and a windproof, waterproof layer is a necessity.

Health and Safety:
Standard safety procedures apply here as in any other travel destination:
be aware of your belongings, avoid unlit and deserted areas at night. It's a good idea to have travel insurance that covers health.

Local Etiquette and Respect:
People in Turkey are very respectful, so try to reciprocate their politeness. When visiting religious places in Turkey, be respectful and dress conservatively, covering shoulders and thighs. The consumption of alcohol in public places outside of designated drinking areas is also generally frowned upon.

Enjoy your trip!