Originally Posted by
ckendall
From Rome to Pompeii (by train), you need to get a Roma Napoli train, then a Pompeii train which if you start early in the morning should be quite doable and then the reverse on the way home. It's about two hours (high speed train from Rome to Naples) if the connections work.
This is true, but beware the
Circumvesuviana (Naples-Pompeii-Sorrento) train on weekends, especially Sundays, if the weather is nice. The train can potentially be packed to the gills with excited Napolitani heading for Sorrento. Mrs. keihin_242 and I had a fairly horrible ride to Pompeii on a Sunday in early May a couple of years back.
Also, Pompeii can become very hot even in the spring, so buy water in Naples (or carry from Rome) unless you don't mind paying the overpriced vendors around the Pompei Scavi - Villa dei Misteri station. Refreshments are even more expensive after you exit the Pompei ruins.
Depending on your plans, you may want to consider an
ArteCard to cover admission to attractions and public transport. Pompeii is 11 EUR by itself; if you plan to see anything else, an ArteCard may be a good idea - you can buy them at Napoli Centrale train station and at many of the sites that accept the card.
If you do take the Circumvesuviana, try to board one of the express trains - they only take 22 minutes instead of 35 to reach Pompeii and you'll stop a
lot less. Timetables are at the link above.