Locative Narrative is a form of Interactive Digital Narrative (IDN) where the readers' location and movement are the main form of interaction. The StoryPlaces platform provides a general toolset for the creation and delivery of these location aware stories. However, while there is existing research on the reader experience with this technology, comparatively little is known about the author experience. We recruited five interactive narrative design students to participate in a usability test of the StoryPlaces pattern-based authoring tool, using observations, interviews, and analysis of their stories to understand their experience. We show that while participants superficially liked the interface of the StoryPlaces authoring tool, they had difficulty understanding the aspects that were less clearly visualised and struggled to test their creations. The patterns enabled them to add complex functionality easily but became a barrier if they wanted to deviate from them. Our findings mostly support Green's five principles of IDN authoring (on the value of visual metaphors and fast track testing), but suggests they need refinement as in application it was important to distinguish between the visualisation of different aspects of the story (location vs. logical structures), and that failure to properly visualise sometimes led to avoidance or displacement of activity rather than a drop in its quality.