I took Rick's advice and bought the Lonely Planet Greece book and it had a great route laid out in it for a month long trip. The only problem is that it listed a ferry from Mykonos (or Mikonos) to Thessaloniki that departs once a week. However, I cannot seem to find that ferry route existing on any of the Greek ferries schedules. Does it really exist? If not, how else can I get to Thessaloniki from the islands and insure I go in a counter-clockwise motion (I am flying in and out of Athens). Thanks!
It may exist, but only "in-season" (May-October). What may be faster and more convienient though is to take the ferry to Piraeus (Athens) and then the train to Thessaloniki. As contradictory as that may sound, connections are more frequent and faster going through Athens. By going that route, you can pick the day you want to travel rather than waiting for a once a week ferry.
That you so much! That helps a lot. I will look into taking the ferry back to Athens and then the train up to Thessaloniki. I plan on renting a car there to later drive back to Athens and stop at all of the great sights along the way.