The B&B itself is in a fantastic location. The neighbourhood is nice and quiet but only a 5 minute walk away from the Vatican itself, and a 2 minute walk away from the subway station.
The room was lovely with a modern bathroom, aircon, wifi and flat screen TV. Dario, the owner arranged transport for us to and from the airport which was incredible, and saved the hassle of getting a taxi which was pretty much the same price, although we met his colleague Rodrigo, who speaks Italian and Spanish but no English. Fortunately we speak fluent Spanish and he gave us some fantastic tips and was very welcoming.
I would definitely recommend going up to the top of the Spanish steps and walking along the balcony both at day and night because you get some stunning views.
For an idea of how much you can cram in, we walked approximately 20km per day (which would be less if we'd used the subway) and managed to see all the main sites in 3 days, including the Vatican and a day tour, Colosseum, Pantheon, Trevi Fountain, Spanish Steps and so so so so much more!
One top tip is don't buy the slices of take away pizza from the really cute looking shops. They advertise it as being about 1euro when they actually charge you per 100g which in the end costs 5-6e. You are way better finding a restaurant and sitting down having a pizza for 8euroes! Also take a map with you everywhere. Very important.