We highly recommend Antonio and Catarina's place. It's modern, clean and has pretty much everything you need. Big enough for 4 adults, we stayed there over a week. Even has enough hot water for 4 people to take a shower one after the other. You can definitely walk everywhere as well, we didn't take the metro once apart to go to the airport. As we stayed over a week, they also offered for the flat to be cleaned mid stay, free of charge, which was very nice 😊