Pompeii/Herculaneum/Archeological Museum: Is this too much is one day?

It’ll be really whirlwind, but if you have the stamina for five-and-half hours outside (in hot, sunny late summer), plus a non-stop spin thru the fantastic museum, it seems like the timing would allow you to see a lot, if not everything you might want to see. We needed large parts of 3 separate says to see those sights, but weren’t rushed, except for Pompeii, which closed early that day.

Make sure it definitely isn’t a free admission day anywhere, so you’re not fighting insurmountable crowds.

Going the first week of September can be problematic enough to hit all three sites in one day because it’s usually very hot in Naples and particularly Pompeii ( there is no shade at Pompeii). The temperature may be 80-83 degrees but the humidity can be 70 percent. Even if the weather was not enough of a hurdle, there are multiple online Italian government notices that all archaeological sites and museums are included in the list of first-Sunday-of-the-month free admission days.
In my experience, whenever top attractions such as these have free admission, you can count on them being absolutely mobbed on free first-Sundays.

With four months remaining before September 2, there’s plenty of time to change the itinerary as all three sites are open on Mondays. If you stick with the current plan, I would go to Pompeii early in the morning before opening time to get in line. You should reserve opening time in advance online to be admitted then. Be prepared for the entry gates to close temporarily once the number of visitors reaches 15,000 as employees wait for some of the morning crowd to thin out before they begin admitting more visitors. Take plenty of water, sunscreen, a hat and snacks. Personally, I would skip Herculaneum so you don’t melt outdoors, but if you think you are not feeling any heat exhaustion coming on, you might be able to power through to see it. The National Archaeological Museum in Naples closes at 7:30 pm ( last entry is at 6:30 pm) so if you go at 5:30 pm to have two hours to see the artifacts found at Pompeii, the crowds may have thinned out, if they haven’t already passed out.
Be sure to check if there is a reservation requirement for free-Sundays to enter Herculaneum and the National Archaeological Museum if you plan to go.

It's better than nothing, but...it will depend on your level of interest. I tend to linger and take it all in. Between Pompeii and Herculaneum (plus a side trip to Oplontis) last week we spent 3 days and about 14 hours total. My wife had had enough, but not me. We also spent 3 hours at the museum in Naples on another day and didn't make it past the top floor.

The tours through Pompeii all tend to do the same route and take about 2 hours which gives you time to take in some areas the tours tend to skip. If that's enough for you then I'd do Pompeii or Herculaneum and follow it up with the museum. Personally, I think the museum is important to tie everything together.

*I have no experience with Askos Tours but we definitely saw more tour guides holding up the Askos sign than any other tour company.

Have you forgotten about Vesuvius, Stabiae, and Oplontis, among other places, like Paestum? Just kidding.

You are not reckoning with the heat, the sun, and the size of Pompeii. It is quite exhausting to visit just Pompeii, partly because of the miles of worn Roman paving stones. You have not told us where you are sleeping before and after. You may also wish to consider that Pompeii has food inside, but Herculaneum does not. It would be too bad if you skipped the Farnese Marbles at the Archaeological Museum.

I have not been to Caserta, but was happy to leave it for another visit to southern Italy.

https://community.ricksteves.com/travel-forum/italy/herculaneum-and-pompeii-questions

We were just in Naples for 3 days. We have been to Pompeii before so didn’t do it again but if I recall, 2-3 hours is needed to give it justice. Don’t forget about the time it takes to travel there.

The museum needs 1-2 hours and Herculaneum 2+ hours. These are all minimum. And again, you have travel time to Herculaneum. We spent the money for a private driver and it was still 30 minutes plus.

I think you would not be doing yourself any favors. It’s too much and you would end up not enjoying your selves.

I would either just do Pompeii or do the museum and Herculaneum.

We did both of them in one day while our ship was docked in Naples, but did not make it to the museum. Unless you want a super in-depth visit, you should be ok.

Just noting that the free Sundays do not stop during high season and the popular sites are absolutely mobbed on free days regardless of the time of year.

Yes it is too much for one day. With 5.5 hours in the sun, heat, and stepping across the boulders that are the paving stones, you will be utterly exhausted. I say do Pompeii OR Herculaneum and then hit the Archaeological museum after resting for a few hours