We had a fantastic stay at Gianluca's guest house. We were 3 couples, occupying it in full. The house looks just like in the pictures:totaly new and comfortable. It has all needed kichen tools, fridge, so we could have nice dinners home. The supermarket is just 3min walk, also there are few small shops just few steps from the house. Metro stop is round the corner. Close to metro station there is a great pizza place Pizzarium, across the street increadible beer boutique with craft beers -both worth a visit. Vatican museum-10 min walking.
I assume it is possible to rent just a room, but in case you are 3 couples and want a totaly comfortable stay - this guest house would be my first to choose. It has a great location, perfect host and all needed comfort!