You can do DTW--xxx--MEM--BNA and back for $118+tax round trip for travel Mon-Thurs or Sat with 7 day advance purchase.... fare requires a 1 day min stay, but you could do nested tickets out and back in one day in Dec., then again out and back in Jan., yielding 3000 on each round trip.
xxx can be one of a number of cities: IND, CLE, MKE, ORD, SDF.... see which midwestern city has availability for your date.
Good luck.