The Leaning Tower is at the northwest edge of Pisa. Borgo Stretto, the Arno and the station are where you spend the rest of your time. Pick a hotel for the walks you will repeat, not for the first photo.
Piazza del Duomo has the tower, cathedral, baptistery and Camposanto on one broad lawn. Day visitors crowd the streets around it. Stay toward Via Santa Maria or the university quarter for a shorter walk back after an evening in the centre.
Borgo Stretto runs from Piazza Garibaldi into the north-bank shopping streets. Cross Ponte di Mezzo for Corso Italia and the route to Pisa Centrale. A hotel near the bridge is a fair compromise between the tower, the river and the railway. The tower is still a longer walk than the map suggests.
South of the Arno, San Martino has quieter streets and the riverside walk toward Giardino Scotto. Stay on the station side for an early train or flight. PisaMover runs from Pisa Centrale to the airport. Pisa San Rossore station is closer to Piazza del Duomo, but not every train stops there.
Summer highs average about 86 °F in July and August, and autumn brings more rain. Get around the historic centre on foot. If you drive, ask your hotel about the ZTL and parking before you enter the old streets.