Valerio's place is beautiful. It is a very spacious house. Well equipped. Very clean. It's just a little away from the metro station. The bus connectivity is great though. The bus number 46 takes you to the city centre and you can catch it from a stop that is 3-4 min walk away. The house is on a walking distance to the Vatican. If arriving from or going to the airport the most feasible option unfortunately would be taking a cab and should cost around 50-60 Euros.