30 day itinerary - what do you think?

I think you have a couple of possible typos; lots of backtracking to Siena (there is a day that you go back to Siena to take the bus to Roma - It would be more efficient to turn in your car in Firenze after all your time in Siena, and take the fast train from Firenze Santa Maria Novella station to Roma Termini station, it will save you a lot of time). But perhaps you want to spend Easter in Siena?

The total extra distance probably isn't great, but I see that you are dipping down to Orvieto and then going back north to Pisa and Lucca. I think perhaps you'd be able to plot a shorter route if you printed out a map of Italy and circled the places you want to go.

I'm not clear on where you are planning to sleep on some nights. I hope those aren't a lot of one-night stops, because that will get old very rapidly.

I am sorry about that first-night bar-tour reservation, but perhaps the four of you will not be zombies on Day 1 like I am.

I think hitting all four islands (Burano, Murano, Torcello and ??) in a single day is pushing it. I'd figure out which islands were my top priorities and try to hit those first (subject to the vaporetto route, of course). I think you'll enjoy the day more if you let it play out naturally and allow time for wandering, rather than feeling you have to go to all four islands in one day. I don't believe I've ever heard of someone attempting it.

Echoing Zoe here: your itinerary looks like it has too much backtracking to Siena, and you've split up Florence. Why not STAY in Florence on day 4 as long as you'll be there anyway, and add 2 more days to accommodate your visits to the Accademia (currently on day 6) and the Uffizi (currently on day 23). There's also much more to see in Florence than just these 2 museums.

Lucca and Pisa are probably best done from Florence: it's not clear where you're staying the night before?

Eliminate all backtracking to Siena: stay there for the duration of things you want to do and then move on (e.g. why are you going back on day 24?)

In short, I'd group things so that you're not jumping around, and could you note where you are staying each night?

Your 2 days of wine tasting? Consider getting a driver unless you intend to taste very little...

Editing to add: I just saw your previous post stating that you're spending 3 weeks in Siena so other than Venice, Rome and 1 night in the CT, I guess all other nights are in Siena? It may have been helpful to mention that here.

With 21 days (Day 4-25) scheduled in Tuscany/Umbria/CT, it isn't clear from your plan where your accommodation lies for this period. To minimise driving times it would be best with a few bases - north, central, south. Currently your itinerary seems quite random and potentially very tiring.
North (5 nights) - Cinque Terre, Pisa, Lucca
Central (8 nights) - Florence, Siena, San Gimignano, Volterra, Chianti
South (8 nights) - Montalcino, Pienza, Montepulciano, Assisi, Orvieto

Sorry that I did not make it clear that we are staying in an apartment in Siena days 4-24, except the one night in Venazza.
I think I will try to reschedule the bar tour in Venice for the following night. On the 4 islands, we will quit if we have had enough after two of them.

Sorry that I did not make it clear that we are staying in an apartment in Siena days 4-24, except the one night in Venazza.

That makes much more sense now! I was getting dizzy before! With staying in one spot for so long you really do have flexibility in many things.

Good idea to move the bar tour.

Have a great time!

"...not being overbooked...". Day three seems to be awfully crowded. A reasonably paced visit to Torcello, Murano, and Burano will take most of a day. I assume the fourth island is Giudecca which is in the opposite direction and the markets are in the center of Venice. If you want to visit all those places, you might want to consider adding another day to Venice. Just a thought from one whose been to all those places -- but not in one day.

Even with your Siena accommodation settled for 3 weeks, I would be wanting x2 Cinque Terre nights additionally booked for your excursion there, and x1 at Assisi.

Day 1. From Siena via Lucca to CT (2N)
Day 2. Exploring CT
Day 3. Return to Siena via Pisa

Day 1. From Siena to Assisi (1N)
Day 2. Return to Siena via Orvieto

This would save you doubling up on some of the long driving distances you currently have planned.

I also think you would appreciate some rest days with absolutely NOTHING planned. I would look at x3, on days 10, 15, 20.

Thank you for the input. It really helps.
Happy travels to all.