We stayed for three nights at Elisabetta's place. It is located about three blocks from the Colosseum, it has a kitchen, four bedrooms and four bathrooms, with a fifth small half bathroom that serves as laundry (only washer, no dryer) and an extra room that works as a play room, with toys for kids. It was sparkling clean, air-conditioned, with thoughtful touches such as coffee and tea, clean towels, little bottles of shampoo and conditioner in the bathrooms.
You have to climb two short flights of stairs to get into the apartment (one outside of the building and one inside, about fifteen steps total).
Elisabetta was there to receive us when we arrived, she explained everything and was very helpful.
This is an excellent apartment if you are a large group and want a central location in Rome.