From Fiumicino Airport/Leonardo da Vinci you can take the Leonardo Express train to Termini Central Station (30 minutes.)
From Ciampino Airport you will find the Cotral bus service that will take you to the metro station Anagnina. From there, take the underground to Termini Station.
How to reach the B&B from Termini Station:
With your back to the tracks take you to the platform 1 exit in Via Marsala go to your right for 50 meters. You will find on the left Via Del Castro Pretorio, we are at number 28.