This is easily the best decorated, cutest room I've stayed in! I also had my best sleep here (out of 4 months travelling) as the bed suits me well. I didn't eat much of the breakfast but the coffee was greatly appreciated. There is a door separating my space (bedroom+bathroom) with the others and that privacy was very nice.
I had a bulky luggage but the stairs to the apartment are fairly wide and shallow, so I didn't find much difficulties going up.
It is a very walkable distance to Vomero but I wouldn't walk to central unless you really love stairs. Fortunately it is a less than 5 minute walk to the metro which brings you there and also to the train station without needing to change lines.
As it was my first time in Italy I wasn't familiar with the transport at all, Laura was an amazing hostess and answered all my questions about where to buy tickets on mobile.