The visitor center is at the end of State Rd 9336. It's being rebuilt after sustaining hurricane damage, so they're operating out of a trailer until repairs are done.
If you prefer to stay on land, you can hike along the Coastal Prairie Trail (7.5 miles one way) or the shorter more scenic Bayshore Loop Trail (2 miles) – both reached through the campground. You can also look for birds (and gators) along the half-mile trail that circles around nearby Eco Pond.