Going the State Park route is always a good idea. If you're going during the winter months you might consider Blue Spring State Park in Orange City - about an hour north of Orlando via I-4 - where you can see manatees. But as the water gets warmer, beginning in April or so, they head back down the St. Johns River toward the Atlantic.
We like to visit Winter Park, a community that is a bit more old Florida-like than what you'd see in Orlando (shopping, arts, and a neat old-fashioned boat tour of the area lakes).
If you're visiting Daytona I'm guessing that you're going to the beach. But if that isn't you're destination then you should consider hitting one or more of the beaches. Cocoa Beach is less than an hour from Orlando via SR 528 and the Gulf Coast beaches (county and state parks in St. Petersburg, Clearwater and either north or south) on the western part of the state are about an hour and a half to two hours away.
Locally, you might want to take in the town of Celebration for the nature trails, shopping, and dining.
Downtown Disney or Universal's City Walk are good for an evening out of dining, the movies and some shopping.
Kennedy Space Center over near Cocoa Beach could be an interest place to go, particular if there's going to be a launch.
Plenty of outlet shopping and a variety of malls right in Orlando.
Busch Gardens in Tampa.
Dick Taylor