I took the same cruise aboard the beautiful R1 over last summer.
At the time the charter service was operated by ATA (American Trans Air). ATA had some extreme problems, though not on my trip, so the contract got switched to World Airways.
I assume you are on the same trip that I took. I took the trip starting in Athens, but it is the same. A few nights in Athens and Istanbul and then 5 days on the ship, Santorini (though I believe it is changed to Crete on winter sailings), Rhodes, Kusadasi, and a day at sea.
If you have any questions or want to talk about the cruise, feel free to e-mail me (check my profile). I've taken several cruises, and Renaissance was by far the best cruise experience, mostly due to the seamless transfer of the sea and shore and air.
BizJet