Rural Hospital Frontier Fairness Act This bill alters the Medicare prospective payment system for inpatient hospital services furnished at sole community hospitals (i.e., rural hospitals or hospitals that are the sole source of inpatient care in a certain geographic area). Specifically, the bill applies a minimum area wage adjustment to payments to sole community hospitals that are located up to 75 miles from the closest frontier (i.e., predominantly rural) state. Currently, the minimum area wage adjustment applies only to hospitals in frontier states. The bill also amends the Public Health Service Act to allow such sole community hospitals to participate in the 340B drug pricing program (i.e., a program that allows entities to receive covered outpatient drugs at reduced prices from manufacturers).