Your passport is stamped at your first port of entry, and then you're good for 90 days. When I went to Scandinavia on Icelandair, I went through immigration in Iceland while changing planes and received a 90-day stamp. I never even had to show my passport till I was scheduled to fly out of Stockholm and the airline asked if I was going directly back to the States or stopping over in Iceland. I was stopping over in Iceland for five days, so I received my exit stamp at Iceland's Keflavik Airport.
I'm told that Turkey just charges you a fee at the border and then stamps your passport.
If you're going to anywhere in North Africa or the Middle East, you may need visas, but Road Scholar will send you a pre-trip packet that gives you all the details.
BTW, doesn't Road Scholar tell you where you're going? I've looked at some of their trips, and they offer a detailed itinerary and schedule if you expand the right buttons. They have a whole bunch of Mediterranean cruises.
Go to the page for "your" cruise. Clicking on program details gives you the option of selecting "Daily Schedule." That will tell you exactly where you're going. Clicking on "Travel details" gives you the option of "required documents." That tells you whether the countries you're going to require a visa, and if so, how to get one.
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