Fredrik had a nice apartment located in a central location of Gamla Stan. His apartment however is located at the top of the building without an elevator, and we had to walk at least 3-4 flights of stairs. However, this was not a problem for me and my group but could be an issue if you are going on holiday with elderly people or people who can't use the stairs.
Overall, my group had a good time at Fredrik's apartment, and it is worth adding that he is very responsive and happily answered all our questions.