The location of the property for sightseeing is really great. However, you should not plan to come or leave with a taxi. Its in a town thats 1700 years old, was never intended for cars and during daylight hours the street in front of the property is like a parking lot (because the traffic doesnt move).
Other than that, Yusuf and Attila are excellent hosts. We got everything we asked for, which wasnt a little. We wanted to change rooms so that all of the other guests didnt pass by our door, no problem! We wanted a 2nd blanket because we each sleep with our own, no problem either! Luggage carried up and down the stairs, despite it being 35°C each time. Yusuf is a great host, takes time for you, is there day and night.
The room itself is a little small compared to a hotel room, however what it lacks on size it makes up on charm. It has a small refrigerator, a place where you could theoretically cook .. but you are on vacation in Istanbul and want to eat Turkish food right? The airconditioning was a lifesaver given that it was 35°C out and helped us sleep at night. All in all the room is everything you need for up to a week in Istanbul while you are out sightseeing.
You should absolutely do two things, 1) read Yusufs information booklet completely before going out sightseeing, he knows more about Istanbul than you do! 2) Eat breakfast downstairs at the restaurant, you get a 10% discount by being his guest and you would have to search around a lot to find food that good. Dont overthink it :)