Let's be honest that turkey is not the safest country when it comes to traveling alone as a woman. I had many sketchy things happened to me in Istanbul and felt unsafe almost constantly there.
However, this flat is the neighborhood I felt the safest in, although I wasn't able to feel completely at ease in Istanbul. There are many cafe, restaurants, and grocery stores just a short walk away.
You can walk to the bridge that connects to the old town or the tram that takes you there is about 5-10 minutes walk away.
Bed in the room is a sofa bed. I'd say just enough room for 1 person, maybe 2.
Pelin is very responsive and helpful. The traditional Turkish bath place she recommended which is just a short walk away is delightful.