In Part I of this two-part series, we examined the design and development of NERVE: A virtual patient simulation created to give medical students standardized experiences in interviewing, examining, and diagnosing virtual patients with cranial nerve disorders. We illustrated key design features and discussed how design-based research studies improved the total learning experience, including the virtual patient (VP) simulations and the instructional features incorporated with the simulations. In Part II, we examine the efficacy of NERVE and the strategy used to integrate the system into the medical school curriculum by field-testing it with 119 s-year medical students, and measuring students' use, reactions, learning, and transfer. We report findings and reflect on lessons learned from the field-test to posit recommendations for improvement and guide the future research and development of virtual patient simulations. [For Part I, see EJ1108013.]