If you are going to Florence driving a car, this is the department you have to use because it has a safe parking. It is not in the downtown area but it is close enough. You can take a bus 3 blocks away (line 23) and get to Piazza San Marco in less than 5 minutes. Also, there is a Carrefour express (supermarket) 3 blocks away. After spending the day in the downtown area you can get a taxi from downtown to the apartment for around 12 euros (3 people)