I've heard that Turkey isn't so cycling friendly. When I lived in south-east Turkey for a bit, I don't recall having seen a cyclist. And drivers can be a bit nuts (ever see a Tofaş on its roof in a morning commute?). There are also very long stretches of road with few if any water stops, and some mountainous regions. If you're thinking of touring across Turkey, take this into consideration. Also be aware of some areas which have incredibly old roads -- like hundreds of years old, and not much more than a single lane in width. Choose routes carefully.
That said, there are some beautiful things to see, lots of historically important locations, and the people are generally hospitable and friendly (if you learn enough Turkish to be polite, and have a dictionary to help fill some communications gaps, this is even more apparent).