Your passport must be valid for at least 3 months upon entering into Italy. We recommend checking your expiration date and renewing or applying for your passport now to ensure your new passport is received back in time for your travel. Check this website for more information: https://travel.state.gov/content/travel/en/passports.html.
It’s advised to take out travel insurance for your trip which can cover you for missed flights, accidents, illness. Etc. We love World Nomad for their robust coverage and fair pricing: https://www.worldnomads.com/usa/travel-insurance.
While most shops and restaurants will accept credit cards, there will be times that cash comes in handy and is the only method of payment at some smaller retailers. For convenience, we suggest getting USD transferred to euro at your bank here in the US prior to departure. Usually this takes 2-3 days for the euro order to come in so please plan accordingly the week or two leading up to your trip.
You can easily get around on your trip without cell service and only when connected to Wifi. All of the suggested accommodation and most restaurants/cafes will have internet you can access, however, if you want to be able to use your phone, this website breaks down the cellular options that might work best for your needs: https://italybeyondtheobvious.com/using-cell-phones-in-italy-dos-donts/. We suggest putting important addresses into your Google Maps and downloading the route so it’s available without WiFi.
This is a great blog post about general tips for traveling in Italy: https://italybeyondtheobvious.com/italy-travel-tips/.