Traveling with a 4-year-old versus a 2-year-old

Once again, we find ourselves with the opportunity for a big family trip. This time my husband has a conference in Trent, Italy, and we are turning it into a family vacation. Nearly two years have gone by since our last trip to Europe, which means our daughter has changed a lot. Here's a rundown of the differences we expect between traveling overseas with a 2-year-old versus a 4-year-old:

Plane: Not much difference here with regard to fare or space, but we are hoping for more sleep on the flight out this time around.
Advantage: ??
Transportation in Europe: Last time we had access to a car. This time we will rent a car for part of the trip, but use trains the rest of the time.
Advantage: having the car, which happened to be with a 2-year-old
Stroller: Last time, we used one. This time, we won't. Having less gear will be a plus, but it will mean more breaks for tired little feet.
Advantage: ??
Food: Like last time, we will be relying on kid-friendly choices on menus. However, I give Italy a tentative edge because I expect more availability of pizza and pasta.
Advantage: Italy (4-year-old)
Naps: Two years ago, we typically got 1 a day. Now they are hit or miss; our daughter will go several days without one, but then crash for over 2 hours the following afternoon. Fewer naps means less difficulty scheduling activities around nap time, although we will have to judge which days she really needs the nap.
Advantage: 4-year-old
Potty time: On our last trip, we were in the middle of potty training. Now our daughter is reliably potty trained, so the only trick will be encouraging her to use the facilities where they are available so as to avoid emergencies later.
Advantage: 4-year-old
Bath: Hotel rooms and apartments don't always have bathtubs. We were worried about this last time, but it turned out that our daughter thought the hand-held shower was like a water park. We're hoping for the same reaction again!
Advantage: ??
Communication: Our daughter can talk and understand much more now than she could on our last trip. This can help us explain new situations to her--or so we hope!
Advantage: 4-year-old

The tally:
2-year-old: 1
4-year-old: 4
??: 3
The 4-year-olds clearly come out ahead, but we will see what lived experience tells us. I will return to this post after the trip to see how these predictions held up.