"Making" STEM Relevant in Underserved Communities, funded by the National Science Foundation, was Pathways project that aimed to develop a research-based model for supporting and evaluating a mobile making program for different social, cultural, and socioeconomic contexts. This project brought making to underserved communities by taking equipment and undergraduate student mentors to afterschool program sites with the use of a van provided by a community partner. Based on iterative design, the project used successive approximation to shape, test, and refine the project work over the two-year pilot period. Evaluation was integrated into each aspect of this work and accomplished in parallel with the program's. This paper describes the program's rationale and design and highlights the evaluation methods employed. It then summarizes key findings from the two-year evaluation effort. Considerations for making programs, informed by these findings, are offered.