We were going to spend 3 days in Berlin and decided to choose Grünewald district out of several reasons: great location near the most beautiful sightseeings, highly rated cafes and different gardens and parks for walking.
Dorothea's house is located also nearby the bus and tube stations and she can give you some advise how to get place you want.
Her house is really big and you will have your own ground floor as a separate area with 2 rooms, kitchen, bathroom and toilet. Near the house Dorothea has a gorgeous garden with different flowers and trees.
By the way Dorothea lives with a very friendly dog (and even for guests) (German Shepherd), so you can feel like "safe and sound" :)