New Italian itinerary with Lake Garda minus CT

The only thing wrong with this is that it's unfortunate you only have 11 days... :-)
I personnally doubt you'll have time to see Pisa. If so, it will be a long day. Start early, which is good because San Gimignano during the day has simply too many tourists. You might prefer Volterra. I did.
It's not enough time everywhere but at least you get to see it.
In Venice start early as well as st-Marc square becomes flooded with tourists quite early.
Although impressive, I think I prefer the rest of Venice. As soon as you are 300 feet from the square or the Rialto bridge, this city becomes magic. A LOT LESS tourists, beauty and art everywhere.
Have a great trip.
Claude

I think this looks great-busy, but great! And it looks like you have some flexibility. I look forward to your trip report.

One small practical thing: I have only been swimming on Lake Garda from Desenzano and the beaches were pretty rocky. Make sure everyone has some flip flops or water shoes to protect their feet. The water was gorgeous.

Day 3 - ROME. Colosseum and Forum tour with a kid-friendly tour guide
company (Pinocchio). Afternoon, gladiator school (Gruppo Storico).
Evening, will walk around the sites to see them illuminated at night.
(Might book guided tour for this.)

Scully, by day 3 you should have enough of a grip on the layout of Rome not to need a tour. Your 2 days are also pretty full, and you're going to be dealing with summer heat so I'd play loose with how much ground you want to cover that evening. Sightseeing solo will allow you to throw in the towel at the point everyone has just had enough.

Play loose with dinner on arrival day as well, especially if you have a late lunch? You and/or the kids could be dragging at a fairly early hour and something quick off the street may be just enough. Maybe even take it back to your hotel/apartment? You need to be up and around at an early hour on day 2 so a late dinner out after that late lunch might be pushing it.

Also, there have been a some posts lately on traffic violations in Italy/ZTL zones. Since you are driving a lot, I would look into the prohibited zones, particularly Verona. I have never driven in Italy so I can't comment from experience but a place to start would be contacting your hotels and asking about restrictions. I would hate for you to get a surprise fine a few months after you return home!

Thanks for the input! We definitely need to keep our eye out for ZTL zones. I've seen those signs before when I've been in Italy, and I know you must pay strict attention because it's all too easy to accidentally pop into one and get a nasty ticket surprise. Ugh.

Water shoes - a must for pebbled beaches. Absolutely. I appreciate the reminder so that I don't have to hear my kiddos whine.

And yes, I want flexibility. I don't want to pack in too many official tours because yes, then we're stuck. One a day is plenty. You're right about the evening tour. No point in wasting money! We are doing the pasta-making dinner the same evening as a morning tour at the Vatican, but that's so different, and not tiring, that it will be okay.

I thought the same thing about dinner on day 1. If the kids are full from a late pizza and/or pasta lunch at that restaurant my friend recommended, we will just get a snack or gelato. Totally up to our mood at the moment. And our exhaustion level. I remember I felt really good after arriving in Barcelona last year on a similar schedule, and I was ready to go for hours. But around 3 pm my husband was exhausted. He hadn't been able to sleep on the plane and I had (thank you, Ativan!) So we took a break and cancelled the rest of our afternoon plans that day. it will be the same this time - if anyone is tired, we'll head back to the hotel early and/or find something very low-key to do the rest of the time.

We definitely have a busy schedule, but everything is flexible and we'll cut things out as our mood and energy warrants. Vacation is about having fun, not being exhausted!

My friend who lives by Lake Como said that we might want to drive up to Austria and Switzerland just to say we've been there. It's because for him, the drive to get somewhere is a big part of the fun. I said I'd rather just stay put around Lake Garda and enjoy the villages we can see there rather than drive somewhere because we can.

In Verona park on Piazza Cittadella. Coming from Corso Porta Nuova, turn right toward Piazza Cittadella just a couple of blocks before the City gate at Piazza Bra (ZTL). There is an underground parking structure under the piazza. It's a short walk from there to Piazza Bra (Arena). See Maps to orient yourself before you go.

Day 4 seems really full. To enjoy Civita and Orvieto you need a good 2-3 hours per place. I would do Orvieto and Siena and give yourself time to enjoy the sites and grab some lunch. Orvieto to Siena is a good 1.5 hour drive. Whatever you choose will be wonderful!