Hi Theresa-in case there was any question, AAA will sell you an International Driver's Permit (each driver needs their own) even if you're not a member. You'll need 2 passport-type photos, but they can likely take the pictures at the AAA office. The IDP is good for one year. You'll still need to bring your regular, actual driver's license form home with you to Europe.
Rental car drop off situations can vary from one rental company to the next, but we've dropped off at airports (and train stations). When you book your rental, you'll get information and a return office address, but you may need to be prepared to look for signs directing you to the car return lot or parking spaces. Are you dropping off the car at a different place than where you're picking it up? The original rental office may have information for you about where/how to return the car, to make the return easier for everyone.
The rental company will also list what insurance they offer, and how you're covered, plus whatever deductibles you'd be liable for in the event of a bad accident. You may have a credit card that offers insurance protection, but there could be restrictions and specific procedures to follow - call them for the details.
Some rental companies even provide free (but sometimes not sufficiently detailed) maps when you first collet your rental car. For covering lots of gound in a country, we've found Michelin spiral-bound atlases to be very helpful - available thru Rick Steves' Website and other places where maps are sold.
Be sure you know whether your rental takes unleaded gas or diesel, the Italian words for that type of fuel, and whether you're expected to return the car with a full tank or not, to avoid getting charged for a refill at prices even higher than the normal price in Italy!