Considering the Rome to Athens cruise that starts Dec 27 in Rome. What is the weather usually like at that time of year? Is the seas choppy? There is one full day at sea that I am concerned about. Also, since we will be sailing on New Year's Eve and New Year's Day, will anything be open? Do you think the tours will still be going on? Any feedback from those who have sailed that time of year would be great. Thanks in advance.