Traveling with young kids

For the stroller, I would look for something lightweight, packable, and big bouncy wheels. The cobblestones, steps, narrow passageways, hills, will mean a rough ride otherwise, and you will be lifting the stroller over things frequently.

I would seriously consider just renting the car seats, your right, two people with bags for four, plus a stroller, then add two car seats....not to mention herding the kids...is a lot.

I would look at limiting the rental car, organizing your itinerary, so that you don't have it where it is a liability. You can not have it in Venice, nor Cinque Terre. If you were planning on Florence...can't have it there. To drive around Tuscany for a few days, sure, especially if you are staying in the rural areas. Do read up on ZTLs, otherwise you will have some rude surprises after you return home, unwanted souvenirs.

For purees, if you are speaking about those pouches that you suck the contents out of, not sure if those are available, most EU countries are trying to limit packaging waste. If your just talking what we call baby food, yeah, that is available, if the pouch is needed, they make reusable ones you fill.

Traveling in Italy with our grandkids a month ago and renting a car for three day trips, the rental car agency did supply a booster seat for the six-year-old. Taking those same kids to Italy six years ago (so, with a 5-month-old baby and a turning-four-year old), we hauled their carseats on planes and trains, and it was very much not fun for four adults to manage those plus a stroller plus a small travel crib. We did feel like having the baby carseat for the planes on that trip was for safety and also so that she could sleep on the planes. You'd have to decide what you think about that for a toddler. I think people ought to be able to rent carseats and booster seats to use just on airplanes --- it seems weird not to accommodate people with paid-for seats.

There are inflatable travel booster seats available --- one of these for your toddler on the planes might be a decent compromise between safety and convenience.

You don't say how many nights you'll be in Italy, but you really don't need to rent a car at all for this trip, unless by "Tuscany" you are planning to stay at an agriturismo rather than in a city or town.

There are plenty of charming medieval towns in the Veneto and in Emilia-Romagna within an hour or two of Venice, and Burano is as colorful as the Cinque Terre, so give that some thought. These two regions closer to Venice have excellent trains and buses, so no need to rent a car or to spend many hours getting to Liguria or Tuscany. But it's your trip and your family and your decisions about the dream trip vs what's easier or more practical with kids along.

In Venice (where we were with the grandchildren for a week), I would park the stroller in your hotel or apartment and get a vaporetto pass. Hop on a vaporetto or get a gelato whenever the kids get tired of walking. Our granddaughter easily walked 16,000 steps a day in Venice, just not all at once. We watched the very few people with strollers struggle over bridges, even with two adults lifting the stroller. Young Venetian kids did have scooters and we saw daycare centers with dozens of little scooters parked outside.

Venice is a city of canals. They are everywhere. The only way to cross the smaller canals (which you will probably be doing many times a day) is via humped-back bridges with steps going up and steps going down. A stroller will be a royal pain doing that.

On the whole, Italians are the friendliest country for small children I have seen. Our kids were oohed over and frequently played with and given small gifts (food, toys) by people of all ages. It's a really fun place to go with kids!

That said, I strongly recommend carrying your child in a backpack over a stroller if possible. Strollers are just not practical in Italian cities for many reasons:

• Sidewalks can be very narrow, and difficult to get through with a stroller. Crowds make this even worse.
• Hill towns can have steep streets, and can be hard to push a stroller up (especially with cobblestones)
• There are lots of stairs (church entrances have stairs, bridges in Venice have stairs), and stairs probably require both parents carrying the stroller together
• The cobblestones are really rough on strollers: we had a compact foldable stroller disintegrate on them in less than a week of use.
• Getting in and out of public transport is a huge pain, even with a compact stroller.

The backpack is more tiring, but having done both in Italy, I'd choose to carry my child in a backpack over a stroller in a heartbeat.

You should have a fun time, though!

I will chime in since I took a trip when my kids were similar ages (6 and 2) when we took them to Italy and Switzerland.

-We skipped the stroller and brought a backpack style carrier (Deuter Kid Comfort Air). I personally would not want to mess with a stroller in Cinque Terre and Venice. There are a lot of hills and stairs, not to mention crowds. A backpack style carrier is also great if you want to do any hikes. If my 6 year old was tired, that meant it was the perfect time to find some gelato and shade. If you go this route, I highly recommend trying one on at REI to see what is the most comfortable, and practice with it ahead of time.
-We rented car seats when we booked our rental car. I believe it was through Avis. We had a booster seat and a convertible style car seat. We had to install the seats ourselves, so I looked at the name/model of the convertible car seat and searched on my phone for the car seat manual in English.
-I'd err on the side of bringing pouches. I know I have seen them at large grocery stores, but in Venice and Cinque Terre you will likely be stopping at smaller markets with less selection. I've seen milk everywhere though it's usually shelf stable and not located in the refrigerator section. Yogurt is always available and often comes in interesting flavors that I don't see at home.

Other tips:
-Pack light and try to book Airbnb style accommodations with a washer if you can. Dryers aren't as common but you can hang clothes to dry.
-If you do check bags, put an AirTag in each one. (Learned this one the hard way on a different trip last month!). Put a clean outfit for everyone in your carry on bags.
-Most importantly, have fun! Traveling with kids can be tough at times, but it the joy of traveling with kids far outweighs the hard parts.