Distance to Big Ten West division schools:

BYU to Nebraska = 897-mile drive
BYU to Iowa = 1,196-mile drive
BYU to Minnesota = 1,261-mile drive
BYU to Wisconsin = 1,374-mile drive
BYU to Illinois = 1,414-mile drive
BYU to Northwestern = 1,424-mile drive
BYU to Purdue = 1,505-mile drive

1,296-mile average

Distance to Big 12 schools

BYU to Kansas State = 977-mile drive
BYU to Kansas = 1,047-mile drive
BYU to Oklahoma = 1,117-mile drive
BYU to Iowa State = 1,118-mile drive
BYU to Oklahoma State = 1,122-mile drive
BYU to TCU = 1,180-mile drive
BYU to Baylor = 1,223-mile drive
BYU to Texas = 1,248-mile drive
BYU to West Virginia = 1,913-mile drive

1,216-mile average (or 1,129-mile average without West Virginia)

Looks like if the Big 12 took BYU and, say, Cincinnati then they'd put BYU in a division with the Oklahoma and Kansas schools and Iowa State