We are planning a very short trip to Greece in June of 2016. Our trip is 3 weeks but we are planning on spending a week in Greece, a week in Italy and a few days in Spain. We are not comfortable driving in any of these places and will be relying solely on public transportation (some flights if necessary). We will have a group of 12 that consists of a couple in their early 20's, couple of women in their early 30s with their 11 year old sons and two couples in their late 40s each with sons in their late teens. We are looking for things to do that will appeal to all. Everyone will be interested in seeing the historical sites and the boys are all interested in the islands. Due to obvious time restraints, we thought we would spend 2 days in Athens and the remaining time seeing one of the Islands.
We need advice on which Island would be best suited for teens but still have an appeal for the adults, also what would be the best for accommodations. Should we stick with Hotels or would a house/apartment rental be better? Is it reasonable to think we can do Athens and the Isles without a car? Are there any other "must sees" for the boys?
I'm sure the answers that I get are based on preference, but I would welcome any thoughts or recommendations. Even if you have recommendations about the other two places (Italy and Spain). Again, we are limited to 5 days in each place and must consider the amount of travel time that it will take. We will be flying into Greece and starting our trip from there. We will use our Eurail Pass for the remainder of the trip until we fly back to the United States.