If you become worn out from art galleries, churches and museums, you may like to take to the Tuscan countryside that surrounds Florence. There are many great day trips from Florence, where you can visit incredibly old cities and villages, and yes, you can visit many more churches there as well.
There are also many bus tours for half day and full day touring of Florence's Tuscan region.
Fiesole
Siena
Chianti Region
Lucca
Pisa
Cinque Terre