Visiting Naples

Marmaduke123

I agree Herculaneum is much pleasanter, more manageable and more accessible for children. I also wouldn't attempt Rome in a day. Get out on the water and visit Capri, take a trip up to beautiful Ravello. Leave Rome and Pompeii for longer trips and a more suitable time of year, when you have retired! Enjoy your big birthday and take care in Naples!

BFBW

Don't bother going unless you intend to eat delicious pizza Of course in addition to it's other attractions. Having previously resided on Capri, I know amongst the best, is here: 

https://www.google.com/maps/place/Pizzeria+Da+Attilio/data=!4m2!3m1!1s0x133b085af8680a8d:0x4c05a57ef382344c?sa=X&ved=1t:242&ictx=111&cshid=1767579781393131

https://www.google.com/maps/place/Pizzeria+Da+Attilio/data=!4m2!3m1!1s0x133b085af8680a8d:0x4c05a57ef382344c?sa=X&ved=1t:242&ictx=111&cshid=1767579781393131

Eldi_Dos

@jdvhsully
Another vote here for The Archaelogical Museum in Naples, it is a wonderful place to wander around, particularly during the heat of the afternoon.The Farnese Bull was the stand out exhibit for me, such a wonderful object.
The Italians take great pride that it did not end up in the Louvre.
I hope you find traveling with children a asset as I have always found, its part of the culture to make children welcome.

One tip I would follow is to have a siesta mid afternoon as most of the locals will be doing in August, this will see you suitably refreshed to go out and enjoy la passeggiata in the evening. One of the memorable sights is to see young Italian families decked out in all their finery enjoying a stroll while the kids enjoy a ice cream, such a contrast from a typical high street here.

Bigphil1474

We did a 2 week mini tour a few years ago including Rome - Florence - Pisa - Naples - Sorrento -  Rome. Mostly by train.  We booked all the main train journeys in advance as well. 

As above, the museum in Naples was on our list of to do's but we just didn't have time. We did Herculaneum and Pompeii. The former is like the little brother of the latter. If you want to do both, I'd say do Herculaneum first, then the vastness of Pompeii will be more amazing. We visited Pompeii in October and even we were waning towards the end of the day though and it wasn't that hot. There is some covered areas, but not much. 

The Circumvesuviana train from Naples round to Sorrento is pretty good - notorious for pickpockets though so take precautions. We used it a few times when we were staying near to Sorrento. We also did the Amalfi coast on a coach from Sorrento. Might be a bit of a trek from Naples though. 

For Rome, we stayed their for 4 days but did use the train to get their from Naples. It takes about an hour so is reasonable time wise, price was good, and the trains are a good standard. Be tough to hit all the tourist sites in a day though, especially if it's hot. If it was me, I'd probably do it over 2 different days, plan ahead etc. The Colosseum is obviously a big draw, but it's connected to the Forum which is far more interesting. We spent about 4 hours exploring both sites. The Vatican museum is always busy, but again you can get lost for hours in there. 

It's feasible to get the train from Naples to Florence (about 3h) and spend the day there as well. They start early. We did the journey down and it's a nice train ride. Might be a bit of a long day though.

fifeken

Underground Caves in Naples, and Procida instead of Capri or Ischia in the Bay.

twopenny

A good idea to change your routine to the Italian one. The evenings are cooler and calmer to walk around in when the locals are out shopping or socialising.
The water trip also but you'll still need shade, hats and such.
Caves also cooler.
The museums also.

You might consider starting early to avoid the heat and huge numbers of tourists and coaches at sights. Relax lunch and set off later.
Also remember that people go home for lunch so buses can be busy midday.

I like Pompeii the best. You might consider umbrellas for shade. Look at the routes before you go so you can pace yourself with the children. Also take drinks with you. The prices from the stalls at the entrance are eye watering.

Look up how to buy your tickets for public transport. It's different. Also how to validate them when you get on board. It's all on YouTube and images. With a large group would be easy to forget.
Get the children to identify the machines to validate the tickets and spot them when travelling. 

Vesuvius, there is a cafe in the car park and porta loos. It's a long uphill walk in the sun. See if you can time it early when it's cooler and sun hats. It's exposed.

Lots of local companies doing day trips but are likely to be busy and expensive in August.

Do not wear anything valuable. Don't have your phone out when walking around. Keep your hands on your bag and put anything valuable like credit cards right in the bottom each time. 
You're going to be in a packed tourist area, distracted by what's around and the group it's prime pickpocket time. 

https://www.worldnomads.com/travel-safety/europe/italy/italy-1-for-pickpockets