The apartment is in the best location anyone could ever ask for as a tourist in Rome. Literally right in between Piazza Navona and the Pantheon - it can't be longer than a five minute walk to these places. Also, Giolitti, the famous gelato shop is right around the corner. There is even a water fountain right outside to refill water bottles.
The place is just what you need and is clean and simple. There are 4 flights of stairs which is something important to consider.