My trip in Oslo was perefct, the appartement is at 15 minutes walk from the Opera also you can walk after 10 minutes on Ekerberg parc, with the perfect panorama on Oslo and Fyords.
The appartement is simple and quiet, the perfect place for 1 person. On the corner you can find all the stuff you need. supermarkets and little restaurants/coffe.
Kari is a perfect hote, she answered quickly at all your questions.