Stay near the water on Sanibel Island.
Day 1
Spend your first day shelling and swimming, taking a break from the beach for a stop at the Bailey-Matthews Shell Museum.
Day 2
On Day 2, head into Fort Myers to Edison & Ford Winter Estates and, if you have kids, the hands-on Imaginarium nearby.
Day 3
Spend your third day back on Sanibel, dividing your time between the beach and the J. N. "Ding" Darling National Wildlife Refuge; go kayaking or try bird-watching in the early morning or evening.
Day 4
On Day 4, drive south to Naples and the sights mentioned in the two-day itinerary, or for even more wildlife, head to the Corkscrew Swamp Sanctuary, a nature preserve east of Bonita Springs.