Before visiting a new location, we often look at maps to build an a priori mental representation of the environment using landmarks and points of interest. No such options are easily available for persons with visual impairment (PVIs). As a result, PVIs are often dependent on others for assistance with any activities that require visiting unfamiliar spaces. This seriously constrains PVIs’ social inclusion and ability and right to independently explore their environment. From our earlier studies with experienced PVIs, we explored existing way-finding strategies and the role of environmental cues in aiding orientation and mobility. Here, we build on these findings to propose a route preview assistance application for PVIs to improve building orientation by helping to create a mental representation of spaces they are planning to visit. We translated non-visual cues into potential landmarks and encoded them into a mapping tool - IncluMap. The mapped building data is used to generate an aural route preview. In the follow-up study with five PVI participants, we evaluated how route preview assistance can improve orientation and route knowledge. We show that even for longer routes (>50 m) with a relatively good number of cognitive landmarks (>5), participants were able to remember and build a mental map. We found cognitive landmarks were useful for PVIs to support re-localization and getting reassurance in complex indoor spaces. Based on these findings we believe that the proposed route preview assistance can be a useful tool to provide orientation and mobility training to PVIs.