Host meet with me at apartment,explained everything about.Gived list with recommended places,in apartment theres all type of Rome guides.
Apartments in reality smaller than on pictures(good photographer).I think for 2 persons is still okay.
To Vatican is about 20mins walk.All other landmarks is around 10-20 mins also.No need to use public transport.
If you have much luggage be prepared for workout,3rd floor with small stairs.