Our itinerary was: (we returned yesterday)
Rome: 3 nights in an Air BnBn
Cruise: Civiteccia (Rome), Salerno (Amalfi Coast), Messina (Sicily), Santorini, Kusadasi (Turkey, Ephesus), Mykonos, and Athens
Athens: 2 nights in an AirBnB
In Rome, we did "all the typically first time stuff" and it was the highlight of the trip, but the entire trip was highlights. Agree with the person who said "you can't find bad food in Trestavere" but we found that to be true all over Rome where we visited. My one food recommendation is a little mom and pop near Castel Sant'Angelo and the Vatican called Cucina del Teatro. I had an amazing steak there, and they owners were very hospitable. But we didn't eat any place in Rome that we didn't like. My suggestion is look for the places that make their pasta homemade and you will be fine.
The cruise was great... ship was Enchantment of the Seas which is a good ship, but not one of these new ones with crazy entertainment options. Probably ready for another update on this one but it was fine, and it was all about the ports, anyway. Enjoyed every one of them, with the surprise being the Messina port in Sicily, where we took a trip to Taormina. Loved that little town. As beautiful as the Amalfi coast, less crowded, and in the shadow of Mt. Etna. Very cool. Santorini and Mykonos are both wonderful to visit, but at the end of the day, they are dining and shopping with stunning views. I don't know what I'd do there for more than a day, so that made them perfect. The Kusadasi stop was also great, and we were looking forward to seeing Ephesus, which is every bit as impressive as Pompeii and any of the ruins we saw on the trip (and we saw a LOT of ruins). And the home of Mary was very meaningful to us as Catholics, but it is historically interesting as well. If that interests you, be aware that the building you see is NOT the building where Mary is believed to have lived. When they found it, it was just a foundation, and the building that is built on top of that foundation is a reasonable best guess of what it would have been like. It's a beautiful place, and I found it comforting to know that the mother of Jesus spent her last years here in such a lovely location after bearing witness to the Passion of Jesus.
And Athens was stupendous. Also exceeded our expectations. The Acropolis, the Acropolis Museum and the Parthenon are as billed. Just magnificent. But we found the entire city to be super. There are some great neighborhoods with awesome rooftop lounges/bars/restaurants all in the area around the Acropolis. We stayed in the Monastriaki neighbohood in an AirBnB that had a rooftop patio, and that was a great selection. Food was inexpensive. Our second day plans got disrupted so we took a bus to the beaches on the south of the city and that was very nice. There are only two things negative to say about Athens... they really need to do something about the graffiti problem. I knew this, and in our neighborhood it wasn't as bad, but overall, big problem. Second, all the restaurants in the neighborhoods around the Acropolis have staff that sit out an aggressively invite you in. That can get annoying.
A few things I learned:
1) I'm pleased we did the Air BnB route in both Athens and Rome. We got exceptional value in both places.
2) We walked a LOT. Averaged about 18K steps a day. I ate and ate and lost 5 pounds.
3) That being said, transportation in Rome and Athens was easy peasy. Contrary to what we read in online forums, Taxi's were easy to get. The Uber app allows you to request a Taxi and it worked easily both time we wanted a Taxi in Rome. The subway was easy to use as well. The Rome subway was very New York like.. busy, a little dirty, but felt safe and pretty user friendly. Athen's subway was much cleaner, and equally easy to use. Don't hesitate, especially if you are trying to save money.
4) Personally, if you are tight on time in Rome and want to cross one "must do" things off your list, I'd skip the Trevi Fountain. SOOOO stinking crowded, and while it's a nice fountain, there are lots of nice fountains in Rome. That felt very much like a "ok we did it, now let's get out of here" kind of activity. That being said, it is not out of the way from the Pantheon. We walked there from the Vatican, and ended up seeing it a couple of times just passing by. There are lots of good places to eat in the streets around it.
5) In both Rome and Athens... cars go wherever they want to go. We ate at a little place in Rome that we thought was like an ancient cobblestone alley... and we had to move our table a few inches when a car drove down it. Not many cars came by, but they do drive down these little streets, even when they are completely full of people.
6) Turkey was great. Of all the locations that was the only one we had any thoughts about safety, but it felt very safe. No hint of any problems. Beware the Turkish rug demonstration if you are not into being hard sold to.
And lastly... I have never been to Germany, but our return flight connected in Munich. Wow... I felt like I was in a library. Such a contrast to a big American airport. Very few loudspeaker announcements, no alarms, no beeping from carts in the walkways, no music, no ads, no yelling. When it was time to board, even then they just put up a sign and people got up and in a very orderly way got on the plane. It was weird, and fabulous at the same time. German precision.