Cruise - Rome, Salerno, Catania

You could certainly do Rome on your own, whether you could squeeze in the four Basilicas plus the Colosseum, you would need to lay out a timetable.

Time from the port to Rome is relatively easy, 1.5 hours or so, no need to book tickets ahead, but the wildcard is when you start. The schedule may say you dock at 7 AM (for example), but then what time can you get off the boat and on your way? That can be an hour or more.

All of the basilicas can be reached using Metro, maybe bus, and some walking. Only St. Peters will take some time at security getting in, depending on the crowds. You can go to the official site now and reserve an entry time and audio tour, but then you need to pick a time that works, without causing disruption to your schedule or a delay, but also not missing your entry.

For the colosseum, probably best to get tickets long ahead, either from the official site or via a tour, again, you have that timing issue.

Then of course you have your deadline to get back to the boat. Unless the boat is overnight in port, trying to fit everything in a day is tight to impossible, it all depends on the time available.

For Salerno, it depends on what you want to see. The big attraction is Pompeii, the train station is near the port, and there are trains to modern Pompeii, with the ruins a walk or taxi ride away. You could take the ferry, or bus, up the Amalfi coast, or even visit the Greek temples at Paestum to the South. You could consider a private driver to take you up the Amalfi coast, maybe a stop or two, and end at Pompeii to view the ruins, getting yourself back to Salerno. Lots of "on your own" options.

For Catania, the main attraction is Mt. Etna, you might consider the cruise tour option for that, or find something local, harder to do by public transport or on your own. Catania is worth a walk around, but not the main attraction in the area.

You probably need to book admission in advance to St. Peter's and the Sistine Chapel as well as the Coliseum.

Etna's appeal depends on how much you enjoy walking on treeless volcanic landscape, and how much of that you've already done.

If you've already visited (or lived in) mountainous areas, then an Etna trip might feel like a long drive for a decent view and a walk around a gravel crater, but not much more. For example, if you've already been to Mt St Helens, Crater Lake, Rockies, Cascades, Alaska, etc. then Etna's views might register as "neat... okay, what's next?"

Of course, if you haven't spent much time in the mountains, then Etna's views might actually be amazing. There are not many places where you can get views like that without hiking.

So it depends on how excited you are to get an "A" quality view. If you're used to "A+" views, then an "A" view might not feel worth the time. It's a matter of opportunity cost.

What might be more exciting and memorable is to visit Taormina and/or Siracusa, assuming you have time (each is about an hour from Catania which is about the time it takes to get up Etna). Of course, if you've already seen coastal Mediterranean towns and ruins, then maybe those places will underwhelm as well. So again, it depends on what you've already seen, and what you (and your kids) tend to be into.

If you're into history, there's a great WW2 museum in Catania. Or maybe you're into food - the fish and vege markets might be novel to you. Or maybe you enjoy churches - there's lots of them. Or amphitheaters - there are ones in Taormina, Siracusa, and Catania itself. Or castles - Ursino, Aci Castello, Maniace, Castelmola. Or maybe you just enjoy people watching. Or riding the metro back and forth. Or feeding cats.

Anyway, I just wanted to point out that although Etna may be considered a "main attraction" for some people (and tour operators), for other people there are far more interesting and memorable ways to spend your time on the east coast of Sicily.