(Actually, we started our cruise in Naples, but that wasn't an option under Embarkation.)
We booked our cruise about a month before sailing and it included an overnight stay in Rome and transfers to/from Naples.
Embarkation was relatively organized, though any North American should be prepared to wait longer to clear immigration and to surrender passport to ship's crew (receiving a photocopy that evening -- to be used for getting on and off the ship during the cruise).