On the 64 Bus route, you are quite literally in walking distance to the Vatican, Piazza Novanna, the Trestavere district, and just about every single thing in Rome that you would want to see. From across the city, it is only a 15 minute/Euro taxi back.
We stayed 3 days and were so grateful for the location of Flora's apartment. It is tidy and effective for a space that you will be leaving and returning to by foot. It felt very secure and was on ground level, and Flora herself was quite friendly and apt to communicate quickly.
I will note that the staircase inside is accurately depicted, and does involve a narrow quarter turn that I almost slipped on in socks. Flora recommends ( as do we) to hold on to the handrail. We did not both carrying luggage upstairs (no real need) and thought it was great. Very typical space for everything in Rome but with an A+ location.