Sofia's place is a cute little apartment right in the middle of Ribeira. This means you have all the nice restaurants right at your fingertips, and an excellent view of the river at about 50 meters from the apartment.
Before we arrived, we kept in touch with Sofia to notify her of our time of arrival, and she always responded very quickley. We were greeted at her place by her mother who explained everything very well, and made us feel very welcome. She also gave us a good tip about the restaurants!
Do note, that if you stay in Ribeira, you have to take the evening chatter of people in the surrounding restaurants as part of the local color. This means that if you like a quiet place, you probably need to look elsewhere.
But Sofia's place is really nice and we were made to feel very welcome.