Physics departments frequently run informal physics outreach programs, often to the delight of their local populations. The programs are typically run as part of the mission of these departments, or as part of establishing broader impacts from their research efforts. While the impact to audiences has long been an important area of focus, more recent research into informal physics outreach programs has shown that the students who help to run these programs tend to experience improved physics identity and develop career skills vital for the 21st century. Prior work, however, has been limited to a small number of institutions with modest numbers of facilitators in their studies. This has left a clear gap in the literature examining a broader population of undergraduate physics students from varied institutions across the country. Therefore, we developed a survey and distributed it through the national network of the Society of Physics Students. The goal of this survey was to measure students' perceptions of their physics identity, sense of belonging, students' mindset, and related constructs, as well as collect information about how often they helped to run informal physics outreach programs. Here, we describe the construction, distribution, and analysis of the survey with attention to both closed questions and open ended questions. Preliminary results from regression models show significant positive relationships between participating in outreach programs with measures of students' physics identity and growth mindset. Findings from open ended questions show significant, interrelated themes highlighting the multifaceted impacts of outreach on areas including students' resilience, internal perceptions, transformative experiences, and disciplinary development.