Here is a great site to see NOAA charts in a "google maps" esque browse experience.
ActiveCaptain - The Interactive Cruising Guidebook - Marina Reviews, Fuel Prices, Anchorages
You'll need an account (free) then go to "X-Preview".
I tried navigating down the St. Johhs and got all the way to Winter Springs with either bascule bridges or a fixed bridge with 45'...but then the charts are less detailed.