I'm thinking from Detroit, but it depnds on where you are going. To get to central or south Florida, I-75 is the better route. Going to Mobile or the Mississippi Gulf Coast, or west Florida, the I-71 out of Cincy to I-65 south works better. To New Orleans and further west on I-10, divert from I-65 to I-59 at Birmingham. That works also for the Texas Gulf Coast, following US-59 south out of Houston.