Hi Riadhou --
I'm glad you have figured out the Tinos>Samos connection. I think this sounds like a great trip. However, both Greece and Turkey will be very hot and crowded in August. If there is any chance you could reschedule your trip to September, I would recommend that.
Be sure to check out the Turkish visa situation. If you need a visa, I suspect you could get it when you land in Kusadasi, or perhaps you could do it in advance, online? But check this out.
After seeing Ephesus, do you plan to rent a car or take buses? We used buses, and the system works very well. A car would give you more freedom to set your own schedule. The highways are good and road signs seemed easy to follow.
If you have time, there is another interesting stop you might make between Bodrum and Kas. Dalyan, which is near the Dalaman airport, is a lively little town, heavily visited by British tourists. This means lots of restaurants and activity, which you seem to like. The highlight here is a river cruise, which passes Lycian tombs carved into the cliffs. You visit a market, and a mud bath, which was very interesting. Dalyan also has a sea turtle hospital, which we found fascinating. We stayed at the Kilim Hotel. From our hotel's dock on the river, we could see the Lycian tombs and all the boats passing by. You might enjoy a couple of nights here.
For your day on Kastellorizo, you can walk along the beautiful deep-water harbor. There is no beach, but several places with steps going into the water, where you could stop for a swim. The harbor is lined with shops and restaurants, where you can linger and enjoy the view. Walk up toward the remains of the castle, for a close-up view of a Lycian tomb. See the short black-and-white film of the history of Kastellorizo, in the cultural center (I think it shows daily, around noon).
I hope you have a wonderful trip!