I loved staying at Karl's place- it was a very cozy apartment with a very large bedroom. He could not have been a more thoughtful host! He met me at the apartment, and took me on a quick tour of the neighborhood to help me get my bearings, show me which restaurants to try and which to avoid, show me where the grocery stores are, and. Eat yet, gave me a tutorial on the train system (which is 3 mins from the front door). It's a very centrally-located apartment, but it's not in the middle of the tourist attractions (which I liked a lot). Everything I wanted to see was accessible by a 10-20 minute train ride (sometimes with connections, but if you're willing to walk a bit you could get away without the connections).
Karl also had some basic items waiting for me (tea, coffee, milk, butter, and bread) which was a fantastic touch! It made mornings so much easier without having to stock up on everything. All told, I found Karl and his apartment delightful!