Alessandra is a real awesome host! She is very helpful, friendly and communicative. She welcomed us in person when we arrived late at around 11pm, got us situated and gave us helpful local tips.
This apartment in Testaccio is close to the center of Rome (about 1.5 miles away from the Trevi fountain). There are 3 or 4 bus lines that connect the neighborhood with the center of Rome. There are excellent restaurants in the neighborhood. You should definitely try the Roman street food "Trappizini" that is only 2 min walk from the apartment.
I highly recommend Alessandra and her apartment.