From TPA to MIA its a fairly easy drive, just stay on I-75 south down the west coast of Florida and then cross the Everglades on the dull stretch of I-75 known as "Alligator Alley", into the FLL area, and then continue on southward towards MIA...Mapquest has the drive as being 4 hrs and 14 minutes and 280 miles...I think the time estimate is a little conservative but close enough...