Mona flat is very well located, and connected to the city center (train station, opera) with several regular buses. The flat is close to Bygdøy too.
The double room is really nice and comfortable. The flat is well decorated and well furnished.
Mona is giving good advice about what to visit in Oslo and in Norway. We had nice talks together.
I definitely recommend to stay at Mona's place. I will chose this flat again if I am coming to Oslo some days.