Martina's place is very modern and trendy, with an updated kitchen and a lovely loft bedroom. We had arranged for her father to pick us up from the train station and drop us off at the airport at a reasonable cost (less than a taxi). He was a very nice, pleasant and friendly old man. While he did not speak much English we were able to figure out what each other were saying. Martina met us at the apartment and gave us some tips on exploring the city. She even had a large bottle of water, milk, yogurt, cereal and biscuits for us for breakfast the next day which was very thoughtful.
The apt is located near to a metro stop and to a museum (which is currently under renovation). There are a few restaurants nearby and a supermarket. We were able to walk to alot of attractions in Naples from her location (although it was a fair amount of walking since Naples is a large city).
Martina lives in another apartment in the same building and is available if you have any issues or questions.
They were changing internet providers while we were there so the internet was a bit dodgy which she did warn me about and did apologize for it. One thing I was counting on was the use of my Orange tourist sim for data, but somehow the large building blocked the cell reception and I was not able to get data from Orange. Fortunately, we were only one night so the internet wasn't too much of an issue.
One other minor thing was that light does come into the room from outside via a large window over the door. You may want to keep this in mind if you are accustomed sleeping in a pitch black room such as myself.

I highly recommend staying at this aaprment when you are in Naples. The modern decor is simply amazing and the hospitality is unmatchable.