Chris,
Sounds like an amazing trip! Gives my wife and I hope- our first is due in October and we are hoping to plan our next trip to Italy within the next year and a half or so. Ill break this up into my suggestions for each part of your trip, based off a few different trips weve had. Weve had good luck booking places off of Air BnB, VRBO, and Trip Advisor.
- Rome: We loved dinner at Da Enzo in Trastevere. The walk along the river after sunset was especially beautiful.
- Southern Tuscan Countryside: Great youve got a bit of time here. Its is very different than northern Tuscany (Chianti Region) in the large valleys, fewer trees, etc. We stayed just outside of Montepulciano on our honeymoon, but that villa would be too small for your group.
--Montepulciano: Visit the copper guy here (Ramario Mazzetti)- very cool place and fun guy to talk with. We had a great dinner at Locanda Cicolina just outside of town. A few shops have walkways down through their Etruscan 'caves' that was pretty fun. Supposedly one of the best Bistecca alla Fiorentina places in Tuscany is in Montepulciano, but we didnt know that at the time. Avignonesi winery was quite fun to visit.
--Montalcino: Fattoria Dei Barbi was a fantastic winery to tour.
--Pienza was a very pretty little village to walk around.
--Driving through the countryside was awesome around here.
--Just be warned- if you want to see the Fiume Orcia, it is not very impressive. We rode bikes to it, and its not very big.
-- I really wanted to go see the Abbey of San Galgano, but never had time. It looks amazing, and has a great story.
https://www.travelhysteria.com/abbey...lgano-tuscany/
-- Dinner at Officina Della Bistecca was quite the event, although we learned from experience that it is not very fun to get back south after the dinner finishes around 1130 pm.
-- We did a cooking class with Stefania Balducci, at Pasta al Pesto in Greve in Chianti. She was great.
-- The winery tour at Antinori was pretty amazing.
-Florence: We had gelati at Gelateria Perche No! I recall it was wonderful. Ive read about the event/show dinner at Cibreo Teatro Del Sale and it seemed fun.
-Cinque terre: We loved it here, but that was in 2010. Ive heard its changed, but we thought it was beautiful, and the walking/hiking trails between the villages would be a fun activity with the kid. The seafood was quite good also, and one of my favorite gelato places was in Vernazza, along the boardwalk in the harbor.
- Modena: If youre a foodie (and rich) try for a reservation at Osteria Francescana. Probably cant get reservations now for your timeframe, but you could get lucky.
If you get time, i highly suggest checking out one of the lakes, especially Lago di garda, but there is never enough time for everything!
Enjoy the trip.