When flying from Sanford, we usually head up to the Seminole Towne Center Mall which has lots of places to eat and of course, tons of shops! The big bonus is, you are only 10 mins from the airport, so you can either check in your bags and keep the car a bit longer, or as you are so close to the airport, drop the car and get a cab.
We find the journey up to Sanford can often take an hour or more from US27, so its wise to leave plenty of time to get there. Im the sort that has to be close to the airport on the last day - no parks for me, but plenty do do a park on leaving day.