Hi you can buy gluten free in Migros in Fethiye, 15 minutes on the Dolmus and its by the harbour. I take my my bread which I freeze before and put that in my case, its hard to buy the bread over there and the Turkish for gluten free is gluteniz, you will manage and just have a great time
o big deal for a gluten free diet in Turkey. İ serve guests already for so long. Of course there are the alternative options to bread: yogurt, fruit, eggs, Turkish breakfast (tomato - cucumber - cheese - olives - salami).
There is rye bread (it is called çavdar in Turkey), but that may contain wheat as well. There is gluten free muesli in Migros from "Doğa", you can find rye crackers and rice crackers, but just in case they might not have them in Hisarönü Migros bring a few packages if you would like them.
For restaurants, be careful with some soups as they might be thickened with flour, do not eat börek and baklava (pastries), you can eat all meats and vegetables... only if they serve you rice with darker bits in there that is a roasted pasta, so you should not eat that rice.
Have a great holiday!
My daughter suffers from coeliac disease and we have been going to Hisaronu for the past 7 years. I can honestly say that it is probably the best place that we have been to for her. If you download the turkish translation available online and take it with you when dining out, the restaurants are all very helpful. Just be very careful of the rice. If it has small yellow pieces in it that is called arpa and it is like pasta so is not gluten free. The food is generally not thickened with flour but don't ever assume. Have a lovely time.