We have a fantastic time in Roma. Livia's house was really well situated. Walking distance to Vatican (around 10 minutes way), good restaurants/ bakery/grocery stores around.
The Metro was just one minute from the house, but really you could go walking everywhere (less than an hour to Coliseum) and we did not use public transport.
The house inside is also very good. Two big bedrooms and two bathrooms with very good shower. There is no living room, but once more, we did not really miss it, as we were leaving the house early in the morning and arriving late at night. Perfect for a city break.