Rome and Florence

From Rome, I would suggest Ostia Antica. Go early in the morning and wander around until lunch time and head back to Rome. This is a worthwhile side trip from Rome given your time there. You can easily fill the rest of your time in Rome without any further trips.

Orvieto is a pleasant day trip from Rome. There are quite a few trains to and from Orvieto each day.

From Florence I'd highly recommend a day trip to Siena . Take the express bus and NOT the train. The bus stops in the historic center of town while the train is out of the historic district and would involve a taxi or extra local bus ride.

Siena would be my first choice from Florence, Arezzo would bey second. Train or bus from Florence.

From Rome, Orvieto is unique for its setting, and there is a lot to see. If you prefer ancient sites, Ostia Antica is the best choice.

I've heard Pompeii is amazing from Rome, but its a really long day. We unfortunately didn't have time for it, so it will have to be on our next trip.

I agree with Zoe's advice on Siena and/or Arezzo from Florence. Montepulciano could also be a nice stop. Will you be traveling by public transportation or car? If you have any questions about Arezzo, feel free to message me - I lived there for four months.

Thank you so much for all your suggestions. Orvieto, Arezzo and Siena it is !!
Anyone been to southern Italy - Abruzzo?

Start a new thread for Southern Italy and Abruzo, you will attract more of those particular experts.

Orvieto is a short and convenient train trip from Rome. The Duomo, St.Patrick's well and the Underground Tour are all must sees! It's a great hill town that's practically a stone's throw from Rome.