Exploring Italian country by car in 3 days?

We are going to Rome for 3 days, and would like to rent a car and spend another 3 days exploring the Italian countryside. Any suggestions or advice? We have to end up back in Rome by noon on the 3rd day to catch a flight. Can we make it up to Florence, or is this too rushed? We would like to stay away from areas affected by the quake. Thanks!