Roberto's place is really really nice, it was one of the best places we stayed in when we were travelling around Italy. It's about a 30 minute walk to the centre but you can use buses which I'm sure are a lot faster - we didn't do this as we wanted to explore the city a bit more.
It's in a really lovely area, completely un-touresty(?).
There is a lovely little cafe on the same road called 'Veli paticceria' if you would like somewhere to get breakfast or coffee in the morning, it does really beautiful pastries and the staff are lovely although don't speak very much English (Which is not a bad thing at all, even more of a reason to go there as it's filled with local people).
Our stay was really lovely and we would definitely stay here again! :)