I stayed on Martin and Elise's houseboat with my 3 sons. We had everything we needed and the boat was clean and tidy. Martin and Elise were so hospitable and really went the extra mile to ensure we had a good time (early check in/late check out, drinks in the fridge etc).
The location is very quiet and peaceful (sit in the hammock and watch the ducks go by for ultimate relaxation) but you can still get into the centre either by bus or harbour bus (i.e. the water bus which goes from just outside Copenhagen Opera House). I downloaded the DOT app and paid for all journeys online which made things very easy. The airport is around 30 mins away by Metro (M2) & then bus (2A), then a short walk.
I highly recommend you try out this accommodation if you're looking for something a little different and enjoy calm and peaceful surroundings.