Rome to Naples Day Trip?

You didn't give the month, which would affect the pleasure of strolling around the historic cultural capital of Naples. I personally think it's too far, but if you buy the Frecciarossa ticket three months in advance, it's very affordable and quick. The museum tends to be annoyingly crowded, and to have almost no English labels. (Reporting, not complaining.) I liked the Farnese Marbles almost as much as the many original items that have been replaced (at Pompeii and Herculaneum) with copies.

There is much more to see, art and architecture wise, than just the museum. Count on waiting in line for a pizza lunch. Unless you are from a remote town with fewer than 10,000 residents, I think the gritty, underfunded streets of Naples are as safe as any city in Europe. That means the same pickpocket and scam awareness you have used in Rome. I had a "gypsy" boy reach in my belt pouch in Rome. Nothing bad happened to me in Naples. That's one person's report.

I think vision is more important than hearing in safely crossing a busy street.

Have you already seen Tivoli (both tourist sites there), Ostia Antica, and Pompeii? Orvieto?

I might not make the train ride just for the National Archeology Museum, but for the museum + rest of the day wandering Naples or museum + Pompeii or Herculaneum, then I would and it's not an unusual thing to do. (I have not wandered Naples, only visited the museum with our tour group.) The last return to Rome by the fastest type of train departs Naples at 19:40; later than that, options are a bit slower.

The Naples National Archaeological Museum is outstanding. If you have any interest in Roman artwork this is the place for you. The very best mosaics, frescoes and sculpture from Pompeii are all here. The collection of everyday artifacts is superb and the Farnese collection includes a number of simply staggering pieces from the Baths of Caracalla in Rome. Half of the Roman art and artifacts I'd seen in boos over the years are located in this museum. If you've been to Sicily, Naples should be no problem for you.

I am also planning to go to Naples from Sicily, currently planning to fly from Catania to Naples, staying in Sorrento. Two questions: 1): can the Museum check my backpack if I go there between the airport and the ferry? and 2): how much time should I budget for the Museum? I'll arrive in the afternoon.
Joanne

Rome to Naples is a terrific day trip, easy and fast from Termini. Archeo Museum is marvelous, don't miss it. Besides all the Pompeii collections they have a great Egyptian section. I did this trip in early November, spent 9 hours there and still didn't see all I wanted to. Rick's Italy book has an excellent walking tour route with all the primary sights, good directions and info about getting around Naples. Two young Italian gal friends went along. We had no trouble with pickpockets, crossing the street or any other issues some people say one might have there. Be sure to see the street of presepi and eat sfogliatella!