We are stopping in Naples, Italy, in August for the day on a cruise. We arrive at 07:00 and leave at 18:30. We would like to go to Pompeii and I am told that Herculaneum is even better. Are these place something we can do by ourselves or is it more practical to do a tour. We generally prefer to do our own thing, even a private tour is preferable to a Cruise ship coach tour. Any advice would be welcome.