Well as for avoiding the big mountains, if you hug the Mediterranean you will miss the best of the Pyrenees, Alps and landscapes of Greece, Romania etc and gain the worst of the drivers. However its stunning scenery. Get your visas sorted now. You could take a ferry from Greece to Cyprus then to Lebanon (although the border between lebanon and israel may be closed) Beruit is a terrific fun party city. Of course you cant take the ferry from Turkey to the Cypriot ports that go to anywhere fun because the country is divided...
A lot of logistical thought is needed. Shame about Syria - I love it. Remember also if you are thinking of camping there is not a lot of wild camping in Europe.
Good luck