Moa is a wonderful host. His home is in a great location. Easy walk to all the sites, but more importantly, it's a really fun neighborhood. Great night life if you're looking for that, but also great food, markets, cafes, etc.
Moa gave us a neighborhood map and it had everything we needed without a couple blocks. (Make sure to buy pizza by the slice from the place around the corner.) From there we could walk to Vatican City or Trevi Fountain or the other sites. No walk was more than 30 minutes.
The place, most of all, is spacious and has a lot of character. On a closed street that is quiet even with the surrounding nightlife. Highly recommend.