Fornarina's place is in wonderful location! The best in Trastevere! and Trastevere is definitely the best for staying in Rome in general! Restaurants, bars and cozy live atmosphere around. Every main attractions in Rome could be reached by foot, but also plenty of bus / tram stops around if you would like to save your foot little bit :) So it is also easy to get to / from the airport by public transport, no need for taxi, etc.
Apartment was great also - simple, clean with everything you could need during your stay.