The location of Maria's place is excellent. You turn around the corner and you can already see the are with the colosseum and roman forum. We arrived in the middle of a thunder storm, about an hour and a half before we were expected that evening. I messaged Marisa to see if we could check in earlier to get our of the rain and she said no problem. We were greeted by an elder man who didn't speak much English but we were able to make each other understood. He even told us which routes to take to the most interesting places in the area. The room was clean, air conditioned, and had a small breakfast. We found a small cafe right around the corner where they serve an excellent, authentic, and reasonably priced breakfast. It's where the Italians were having breakfast. When you look out the window from Maria's place there's a small courtyard that is actually the back to that cafe, you will notice the world map on the back door. If you take two rights in the street to the other side of the building you will find it quickly, same map, small terrace.
Anyway, we really enjoyed Marisa place and would definitely recommend it if you're looking for a central location and just a clean and affordable place to crash. Grazie mille Marisa!