I've just returned from 15 days in Italy - Florence, Venice, Sorrento (base), and Rome and with some advanced organization, found everything very easy to navigate through.
Most of my activities and tickets were pre-registered / purchased however there were a few instances in which I purchased on site without problems. I carried and presented (with my passport) my original CDC card inside a waterproof name badge holder however I think a laminated copy would have worked fine.
Everyone was wearing masks indoors, most people outside were not wearing masks.
I did the Elume Covid Test right before my flight although there were neighboorhood pharmacies -- of the two that I checked, they offered walk-in tests sans appointments with results emailed within 1 hour. I never saw any lines at these places although there were some minor lines at the train stations.
Along with having the covid test results, there was extra (but easy) paperwork to fill out during the return flights.
I'll check back this weekend and answer any specific questions for those traveling soon.