Ciao Melany,
You can take the train from Rome to Pisa but Italo does not do that route, you have to take Trenitalia. You can also go to Pisa from Florence. You can check timetables on trenitalia.com - you can buy your ticket ahead of time but don't absolutely have to (from Rome) but might not be able to from Florence since it will be a regional train. If you can't, don't sweat it, you can buy your ticket at the station right before getting on. Regional trains don't have reserved seating so tickets are not for a specific seat, you just punch your ticket before getting on and sit wherever you want.
Pisa is definitely walkable! It is a small college town... from the train station just head north, you'll pass by the main shopping streets and arrive at the Arno. You can keep going north and will see signs for the tower... I think it takes about 20 minutes to get there walking if you don't stop along the way.
A whole day in Pisa sounds wonderful - I really like Pisa. I suggest you get a ticket for all of the monuments in the Square of Miracles and climb to the top of the Leaning Tower. It is a unique experience! I also really liked the museum (opera del duomo) and the Camposanto with the frescoes saved from World War II bombings, fascinating!
The baptistery is also very neat - wait and stay until they close the doors (like every 15 minutes) as they do voice demonstrations of the acoustics inside, it sounds wonderful! Of course, also visit the cathedral - the mosaics over the main altar are breathtaking as is just the atmosphere.
They've opened up a walk along the last sections of the medieval wall around Pisa that you see right behind the square - see if you can climb up there to get a special view over the square.
If you still have time after all of this, head to Piazza dei Cavalieri to admire the Palazzo dei Cavalieri (home to the Scuola Normale Superiore di Pisa) and the Palazzo dell'Orologio with its pretty clock tower.
If you head back toward the Arno river, you can visit the Palazzo Blu and the current exhibition on Artemisia Gentileschi.
Make sure to pass by the small church along the Arno called Santa Maria della Spina, a major masterpiece of gothic architecture in Italy ;-)
Share and Bookmark!