Family of 4 August Itinerary

You’ve listed 9 potential locations over 10 day trip
That’s too much
Your time will be spent getting to and from and not actually being there

Pompeii as a day trip from Rome is brutal
Consider Ostia Antica instead

With just 10 days—how many NIGHTS?- I’d pick no more than 3 locations

At first glance, it looks to be too much for ten days. Are flights purchased yet?
Just as a point of comparison, with ten days, I'd do either Lakes-Dolomiti-Venice OR Florence/Tuscany-Orvieto-Rome and I would save Pompeii for a future trip. There is so much packed into every little nook and cranny in Italy that I think it is best to explore a smaller region in depth versus covering a lot of ground. I travel somewhat slowly, but I think a somewhat slower pace might be in order for a family of four.
Remember you'll need time to either do laundry or have it sent out to be done at about the half-way mark.
If you have more than ten days, still write out each day with specifics including transport time--that is still how I visualize and plan a trip after many years.

We are going to Italy next June with our 14 and 10 year old boys. This is our itinerary, all via train:
Rome - 4 nights
Minori - 4 nights
Orvieto - 2 nights
Venice - 3 nights
Varenna - 3 nights
Milan - 1 night

Are you driving? Otherwise Cinque Terre is a wonky train connection from Venice. We drove there from Volterra and back in one day and it was a long day. (But one of my favorite days ever) We could see Pisa from the autostrada so it's on the way.

Everyone is going to tell you your plan is over ambitious, but think about the trips you've gone on with your family before. Did you need downtime or did your kids get bored? We went to Singapore and Indonesia in 2019 and my kids didn't want or need any rest days.

I know that right now you are just throwing out ideas to see what is doable. For a ten day trip I think you are going to have to really narrow down and prioritize your choices. I don't see how you could get to all of those places you mention in that time frame. Each is a destination worthy of time and exploration. At the most three bases with about three days in each place seems doable: maybe Florence, Venice and Rome, although those are all places you have been before but are key destinations for a first time visitor. Cinque Terra seems to be the outlying destination on your wish list and I would just skip it on this trip. Lots for kids with those interests to see and do in Rome. From Venice you may have time to do one day trip- Padua? Verona? Murano/Burano? I think kids that age would enjoy Verona more than Padua. From Florence you could do a daytrip to Sienna or arrange a driver to see the surrounding Tuscany towns. Look up Roberto Bechi at “ Tours by Roberto.”. He is featured in several RS Tuscany productions. We did a daytrip tour of Tuscany with him a few years back. He offers small joinable tours and private tours tailored to your interests. Since your son expressed an interest in Orvieto you could possible stay overnight there as you travel from Florence to Rome. I have not been to Pompeii but not sure how doable that is a daytrip from Rome, in the August heat - probably an extremely long day. There are lots of opinions and info on doing it as a daytrip on different travel forums so you judge what works for your family. You are smart to look at flying into Italy through one city (possibly Venice) and flying out of your last destination (possibly Rome). Enjoy your trip planning and your trip!

https://www.ricksteves.com/tours/italy/venice-florence-rome

https://www.ricksteves.com/tours/italy/heart-italy

Check out the "Itinerary" for these tours to see what might be possible in 'roughly 10 days'

Keep in mind the tours have a dedicated bus with door to door service; your travel will take longer.

I also second the idea to do Ostia Antica rather than a mad day dash to Pompeii from Rome ( particularly on you tight schedule)

You do not say where you are from, so whether taking time to go to the Dolomites for a mountain experience would be worthwhile is hard to say.

I agree with others who say you have too many destinations for your time. Don’t even consider the Dolomites. Another reason to scratch Pompeii from your itinerary is that at the end of August it likely will be suffocatingly hot, and there is no shade. Orvieto might be marginally less crowded than some of the other places on your list.
One thing you might find helpful is to list what you want to do/see in various places. Then, you can see how much time you’ll need in them. Don’t forget to factor in the time lost to packing, checking out, traveling to new stops, getting to new lodgings, and checking in. (1/2 a day or more )

Ten days (nine nights)? I suggest flying into Venice (but not out of Venice unless you fly out late morning because Marco Polo airport is not convenient to get to for an early morning departure unless you take a water taxi that costs in the three digits). I would sleep in Venice a minimum of three nights so you can spend one day getting lost. Your first night there, hop on a vaporetto (water bus) at twilight from one end of the canal to the other i.e., between the train station and San Marco square. By touring the canal at dusk, you won’t see the decay on the palaces exterior that line the Grand Canal. Instead, you’ll see the interiors of the foyers fully illuminated. The experience will take you back in time.
From Venice you can take a direct train to Florence (2h 15m). Make sure you buy your Uffizi Gallery tickets no later than the month of Jun because this museum sells out two months prior. Afterwards, walk over to Accademia to see David. I also suggest buying Rick Steve’s IT guidebook 26th edition that you can download on his app.
From Florence take a train to Orvieto (2h 15m) and store your luggage at the station and then explore the city. The train to Rome takes 1h and I highly suggest sleeping in the Trastevere neighborhood which is very bohemian like. You can then fly home from Rome.
Remind your son that he is 13 and will return to Italy and visit the places you didn’t have time to see.

Just a word of reassurance. Since your son "loves mythology, sightseeing, history, beautiful towns..." you really can't go wrong anywhere in Italy. As MaryPat pointed out, he's 13, he'll likely have many more chances to see more of Italy (and Europe, and the whole world).

Will you rent a car or use public transportation? If the latter, sticking with the cities will be a much better use of your time and energy. If rental car, then whoever is going to do the driving really needs to study up on Italian traffic laws to avoid costly fines.

Another thing to study up on is some basic Italian. You'll all feel more comfortable throughout the trip if you have a working knowledge of the language to understand street signs, menu items, how to ask for the restrooms, etc.

Hi Heather -
I'm piling on with the rest of the folks: you have way too much for way too little time. As far as how much time you accurately have to work with, how many NIGHTS will you have ON THE GROUND in Italy? 10 nights in the country is different animal than 10 days of travel which could include arrival day, which is always a partial, and a travel day home.

Can I do a "for instance" itinerary with a guesstimate number of days? Skipping Milan entirely - as you don't have any interest in seeing it anyway - and flying into Venice...

Overnight flight to Venice
Day #1 - Venice (this is a partial day and could be a jet-lagged one). Sleep Venice
Day #2 - Venice
Day #3 - Transfer by train to Florence (partial day)
Day #4 - Florence
Day #5 - Florence - day trip by trains to Lucca and Pisa
Day #6 - Florence
Day #7 - Transfer by train to Rome/partial day)
Day #8 - Rome
Day # 9 - Rome - day trip to Ostia Antica
Day #10 - Rome
Day #11 - fly home from Rome

You see that I've eliminated some locations and trimmed the entire thing down to just Italy's "Holy Trinity":: Venice, Florence and Rome. While you've already been, the other 3 of traveling companions have not, and moving 4 people from accommodation-to- accommodation eats time so it's often more efficient to unpack ONCE and just day trip, where possible. Florence is a really good base for any number of those so if you think the 2.5 days I've allotted to explore that one is too much for your family, add another day trip (by bus) to Siena.

As well, longer stays make apartments more comfortable/economical choices than hotels when traveling with a group. With 4 people, you might enjoy the sort of space apartments can offer plus the bonus of a kitchen for leisurely breakfasts in your PJs.

I've substituted Ostia Antica for Pompeii as the latter is a really brutal day from Rome unless willing to take it on independently by rail. Practically all of the escorted day trips from Rome are by bus, and involve 6+ hours of sitting on the things: no fun for teens/pre-teens. A good chunk of that time can be shaved by taking a fast train to Naples (not inexpensive if buying day-of tickets) + commuter train to the scavi. That said, Ostia Antica is much, much closer to Rome, and can be reached by very inexpensive local train. Save Pompeii for a future trip that includes Naples (especially the archeological museum where many treasures from the excavation are housed) and more of the Sorrentine/Amalfi Coasts.

Cinque Terre: I've taken that one out too. It CAN be done as a long day trip from Florence but I don't recommend it. If the trajectory of numbers continues to track upwards, the CT could be positively heaving with visitors, many of them daytrippers, next August. That one deserves 2 nights - time you don't really have - and is weather dependent as far as hiking the trails 'cuz they usually close those when it rains. If determined to do it as a day trip, let us know as there are two trains - one from Florence and another one back to the city - that cover ground in the shortest amount of time: just under two hours to/from La Spezia + additional time for short train rides to the any of the 5 villages from there.

Rome: LOTS to see there so I wouldn't cut allotted time any shorter than I already have!

If you can add days, so much the better as Venice could use another one, and maybe you could add 1 night in Orvietto on the way to Rome (as much as I don't recommend 1-nighters.)

Some stuff to think about? :O)