Studies that follow teachers for multiple years are unfortunately rare in educational research. To help "connect the dots" between teachers' participation in professional development meeting and student learning, I conducted a mixed-methods study that followed high school teachers in and out of a school-based professional development program to explore what they learned about student thinking, the kinds of formative classroom assessments they designed, how they used the assessments in their classrooms, and what their students learned. This case study presents the multiple practicalities my research team and I encountered in the course of collecting data in public high schools between 2010 and 2014 to shed light on the expected and unexpected challenges that came up as we collected each source of data. My intention is that by bringing the reader "inside" the data collection process in a school-based, mixed-methods study, I can inform future researchers as to the logistical challenges that may be anticipated when collecting both qualitative and quantitative sources of data across long periods of time. [This content is provided in the format of an e-book.]