Yes, we are not much the same, are we?
I've not been to Rome, but I've spent time in Naples and the Amalfi coast. I've also spent time in Mexican and Central American towns and cities that structurally aren't so different from Italian places I've visited. My first kit, bought especially for such places, were:
DA10-17, DA18-250, and FA50/1.4
Those have served me well across North and Central America. My lens accumulation has grown a bit since then. Of what I now have, my absolute minimal kit for such places would be:
Zenitar 16/2.8; DA18-250; FA50/1.4; Nikkor 85/2 and/or Tak-B135/2.5; Raynox DCR-250
The Zenitar, FA50, Nikkor and Tak-B for lower light in appropriate spaces. The 18-250 for everything else. The Raynox can fit on any of those except the Zenitar. And expanding that kit a bit, I'd include my new Tamron 10-24, and my Bellowscope with a few tiny enlarger lenses.
But on a honeymoon, why use a camera outdoors?