Today, take the fast train from Rome to Florence, check in to your hotel and explore the old town of Florence on foot. Use your skip the line tickets for the Duomo to go all the way up.
Day 2: Pisa
This morning, you will have time to explore more of Florence. Later check out from your hotel and head to Pisa by train.
Here you will see the leaning tower. In case you want to go up the tower, advance bookings need to be made.
Later in the evening take the train back to Rome.