It is so easy to visit all over Turkey by bus from Fethiye, as long as you don't mind the long bus journeys, which can be very interesting. Amasya well worth a visit, 18 hours from Fethiye.
I have also just completed a fantastic 8 day tour of Eastern Turkey starting at Trabzon which was 23 hours by bus from Fethiye and coming back from Diyabakir 25 hours. The tour visited everywhere of interest inbetween these towns. Travelling along the borders of Georgia, Armenia, Iran, Iraq. The journey back from Diyabakir was very close to the Syrian border although I was a lone female traveller I experienced no problems. So many incredible and beautiful sights to see in Eastern Turkey I recommend it to you all.