Mary Cain should run the 2000m at that meet. The 2000m event is rarely held in those meets in the US so Mary should run at that meet. 2000m is only 400m extra after a mile and that distance should help gain endurance for milers. Then she will have us junior records in every middle distance race at 800m(assuming she'll get that record in millrose games on feb 15), 1000m(again assuming she'll get the record in boston university on jan 16), 1500m, 1 mile, 2000m, 3000m, and the two mile.