You’ve been to so many places in the north of italy, so unless you’re looking for a repeats, head south. Naples is the big city, with piazzas galore and other attractions, but “relaxing” isn’t how I’d describe it. Did you see Naples, Pompeii, and/or Herculaneum during your trip at the Amati Coast?
Last November, we had 12 days total, starting in Naples (that’s where we flew roundtrip in/out), but then rented a car and drove to/around Puglia, eventually turning in the car and taking a train back to Naples. There were two of us, and we rented a “mini” sized car, but were given a Ford Puma SUV. Five of you, plus luggage, would likely want at least a minivan, but there were lots of those at the rental lots.
Weather was quite nice, except for three days when it rained, and one of those, in Lecce (I’ve corrected my original spelling), it absolutely poured. In Puglia, we stayed first in Altamura (the City of Bread), then Lecce, then Martina Franca. Martina Franca, with its old town as well as a more modern part, was my favorite, but Lecce’s a bigger city, with more lodging options and sights. Our final night was in big Bari, after returning the car and from where we caught the train back to Naples. Scenery and outstanding small villages were abundant, and they’re proud of their local wines. Primitivo red was my favorite.
We’re going back to Puglia this coming November for more! My sense is it’s currently a much less-crowded part of Italy compared to Florence, Venice, and Rome (and until it gets more discovered), and that the tourists are mostly other Italians, not the International crowd.