The apartment is in a wonderful location. It is quiet with many wonderful restaurants near by. The air-conditioning is a big plus for hot summer days in Rome.
You can walk to local sites but I recommend a tram ticket. Save your energy for the many steps up to the apartment.
Directions to the apartment from the airport can be tricky. The train from the airport and bus to the apartment are different tickets. You get train tickets at the train station and bus tickets at small tobacco stops. Make sure you get tickets for the right train out of the station. The bus to train transfer is very close...but not exactly in the same location. The transportations is not very hard, but I would strongly recommend google maps or printed maps for transfer points. Otherwise take a taxi.