You are so cute with the question about the visa to Europe lol
The answer is a definite no that you do not need any visa anywhere in Europe unless you go to Russia.
I think if you want to do Greece the best tour would be 14 days Greek Island Hopping. You visit Athens, Mykonos, Ios and Santorini for 3 nights each. You got your cultural fix in Athens, party in Mykonos and relax in Ios and Santorini. Those are the most popular islands