We stayed at Mari's apartments for 5 days. Actually, that's not detached flat, it's more likely to be a room with own kitchenette and toilet (I suppose that guests should be informed in advance), because you entrance firstly in small hall with 3 doors. On the right side there is Mari's door, on the left side unknown door and the central is yours. So you have little room, kitchenette without door and the toilet with shower, washer and etc. Even though you have the key for your door, this door is usual for doors inside flat, so you can hear everything from the hall including host's guests. Apartment is really small but cozy and you can find everything you need. It's little bit noisy at night as the windows are at busy street with ambulances and motorbikes. Mari nicely offered us ear plugs. By the way, on the second our day we met a cockroach in the kitchen.
The main advantages of apartment are its close position to subway station and supermarket. It is one station by metro to Vatican. Mari was very kind and nice and she was always ready to help us.