There is no mention of a "thin, dark, passageway", at least in the original. This description refers to the backstairs, before the landing and apartment itself.
Immediately behind the apartment threshold, there is a [dark] entry. The kitchen is separated from the entry by a partition; that is, there is no 'substantial' stand-alone kitchen per se; it's just a corner in the entrance area. This simply indicates very modest if not scanty conditions.
The door to her room is also just there: she was able to point to it right from the entrance door, inviting Raskolnikov to enter.