I had a lovely stay at Kerstin's for a few nights in between apartments in Copenhagen. It's a homely, quirky space with lovely decor – a true local experience in the city centre. While the bathroom can be tight (the shower is above the sink) the rest of the apartment is quite spacious and she kindly had lots of kitchen essentials for me to use.
It's a great base for a single person in Copenhagen – I recommend exploring the Islands Brygge neighbourhood on foot or bike, making sure to stop at Andersen Bakery and Il Buco.