For another approach to the river, try River of Lakes: A Journey on Florida's St. Johns River, by Bill Belleville. In this book, Belleville travels down the full length of the river, giving the reader a natural and cultural history of the waterway along the way.
The website and the book share a common goal, as expressed by Belleville in the introduction to River of Lakes:
"... you might even feel the urge to put the book down and go out on the river to see it for yourself. I hope so -- because I believe we don't protect what we don't value. And one of the surest ways to value any place is to connect with it, even if only a little bit."
Both the book and the website will give you practical information on how you can visit the river, and make that personal connection.