We did this as a shore excursion from our cruise. We were met at the pier by a super nice guide and then proceeded on a very long march around Naples. First to a ticket booth were we got subway tickets, then to a subway stop, on to the train station and then a run through the station to catch a train that was late and not at the station!! Once near Herculaneum we had a nearly one mile downhill walk to the site on uneven sidewalks and lots of traffic! All we could think of was the walk back!!! My husband was so tired by the time we got to the visitors center and looked down at the ruins and all the trudging around he'd have to do that he decided just to wait at the entrance.
I want to stress that our guide was terrific! In no way was this lousy tour his fault, it is set up for extremely young and fit people! The travel time eclipsed the actual time at the ruins. In the end, we had our guide hire us a van taxi to take us back to the port. Not one of us wanted to repeat the long walk uphill, train, subway or walk through mad traffic to get back. BEWARE!