day trip from Siena to Roma
Buongiorno!
if you take the bus from Siena to Rome, it will take you three hours. Once you arrive at the bus station, you'll have to reach the places you want to see ... Rome is a big town and it will not be easy/fast to move from one monument or museum to the other! There are so many things to see - 1 day is probably not enough! Personally I think that, staying in Siena, it is better to make day trips to the wonderful Chianti-area, to the Val d'Orcia area, to Florence, to Lucca ...