We didn't want to have to drive between the cities, so we opted for the train. We went with the Eurail pass for a single country (Italy, duh!). We are honeymooning in style, so we went with first class.
We will be taking the train from Rome to Florence, Florence to Venice, Venice to Naples, Naples to Pompeii, Pompeii to Naples, and Naples to Rome. It's going to be a lot of traveling, but it's going to be so much fun! I am SO ready for this honeymoon! Only 48 days until we leave! (Holy crap! That means only 47 days until the wedding! :S)