Sorrento-Pompeii-Naples Archaelogical Museum-Sorrento

Although bag checking is not risky, we prefer to visit sites without our luggage if possible. Would you have paid for two taxis in Naples with the luggage? If you will have taken a ferry to Capri or Positano, you don't "need" another sealed air-conditioned cabin ferry with few windows and no open deck access.

You can allocate 3 hours for Pompeii, but it's easy (if not too hot a day) to spend 8 hours there. That's your choice. If you can visit a museum at home with Roman frescoes and sculptures, maybe you don't need the Naples museum. Do you want to see the Farnese Marbles? Have Neapolitan pizza or pastry?

I'd suggest 5 or more hours at Pompeii, last two hours of the Naples museum, and dinner in Naples. Check daylight hours and museum closing times for your exact dates. (I'm not a guided tour person.)

You can totally do it same day. Get an early start in Pompeii and you’ll likely hit your limit by lunchtime. Take a good lunch break and you’ll have plenty of time for the museum. The ferry might not be feasible, the last departures (when I was there) were kind of early (3pm-ish.)

we did pompeii in about 3 hours, were there right when they opened. we were actually disappointed in pompeii, one because of the enormous amount of tour groups, and i mean enormous, there were so many people in these groups, it was hard to see some of the sights. and second a lot of the things to see in pompeii were simply closed, either because of restoration, or they changed how you view the item of interest and couldn't exactly go in, but maybe view it from a gate.

you can easily do pompeii first thing in the morning, and do the museum before they close later in the day

we actually enjoyed the museum better than pompeii, and Herculaneum over pompeii as well

Thanks for all of the feedback! After more research, I booked a private tour of Pompeii with Antonio Somma, who is recommended by Rick Steves. He assured me that Pompeii in the morning and the museum in the afternoon is a fine plan. We'll follow with pizza, then head back to Sorrento on the train. I would love to add Herculaneum, but that's probably pushing it!

I would love to add Herculaneum, but that's probably pushing it!

No "probably" about it. Pretty sure you would feel like Wile E Coyote just after hitting the canyon floor.