Can warmly recommend Christina's place for your stay in Copenhagen.
Location is excellent and the outside is quiet. Metro is very close and there is also a bus line that has a stop next to Christina's place. Sunday morning I walked to the bakery that is 5 minutes away which was very nice :)
The building is quite old and the sound insulation is not good, so if you are a light sleeper I recommend wearing ear plugs. Personally we had no issues. The staircase is also extremely steep, so if you have heavy luggage, be prepared for the climb to the top floor.
Christina's apartment is very well decorated, it's very warm and welcoming. Everything worked as it should. The apartment was also very very clean and we appreciated that.
Thanks!