For efficient and effective learning, intensive-mode programs have increasingly focused on threshold concepts -- transformative, often-troublesome, moments in learning that represent the development of key knowledge. Threshold concept theory has support in the context of content-based, disciplinary domains, but questions remain about its applicability to curricula that have broader aims. This study investigated the 'fit' of threshold concept theory to participants, many of them previously marginalized, in an intensive Widening Participation (WP) program at a regional university in Australia. Thematic analysis of data from focus groups, comprised of students and teachers respectively, revealed that participants perceived not only the development of key conceptual knowledge as integral to learning, but that they also recognized that acculturation, metacognition, and affective attributes were important for success. This finding suggests that a narrow focus on academic knowledge -- (both content- and skills-related) -- is inadequate in programs that aim to include previously marginalized students in higher education.