Rosa's apartment is in a great location! The only time I used the bus was to get to and from Roma Termini, otherwise I just walked everywhere!
Rosa was a fantastic host. I highly recommend her if you're visiting Rome. She really took great care to ensure that i was safe, comfortable, rested, and even fed! There's a mini fridge in the bedroom which Rosa made sure had plenty of water, and food that met my dietary requirements. Really felt like home.
You will enjoy your stay at Rosa's place, and you'll enjoy the location as well! Its always lively at any time of day or night :)