As you may know, the most hazardous part of fishing the backcountry is navigation. There are many opportunities to run aground on oyster bars and limestone outcroppings. Even the best charts will not eliminate all of these exciting events for you. The maps shown below will help, but it is sometimes difficult to know exactly where you are in relationship to the chart because you are down on the water...and you cannot see around points of land and islands. Channels and inlets are sometimes hard to decipher from shores of islands. Sometimes you just have to cruise around slowly to get your bearings...or not! Take your GPS and capture routes that work..so you can go back later...or get home in the fog.
There are no "official" channel markers in Mason Creek , St Martin River, Fish Creek, Chassahowitzka River and Pirates Cove -- popular backcountry destinations. The PVC ones you see there were placed by anglers. When storms break them, they may not be replaced or repaired until an angler takes the initiative to do so.
The best approach to learning the navigation of these waters is to get a good map and get someone to go with you who knows the creek or river you intend to fish.
Google Earth now has a free version that is incredible. Down load and run the installation to get amazing aerial photo maps.
Jim Adams says the detailed (7.5 degree) maps of Homosassa and Crystal River are the most accurate of any maps you can get for depiction of islands in the backcountry (see map numbers 50898, 50254, and 50973). These maps do not contain navigation aids such as channel marker numbers. They also do not show local navigation paths such as the Nature Coast Canoe Trail.
TrackUS makes some great charts of the Homosassa and Crystal River areas. They are semi-waterproof and fold (they will absorb water if you leave them in water too long). The maps show topography (islands that submerge in high tide), oyster bars, canoe paths and boat ramps. They also suggest locations of fish species. Blow-up sections show details of main navigation channels. Larry Jordan uses these charts rain or shine. They are not as accurate as the US Geological Survey maps for land mass distinction.
Standard Mapping Service Florida makes some great plastic-coated aerial maps. These show land mass and waterway details. The colors give an indication of water depth. Map F126 shows the Homosassa and Crystal River area. The map does not fold...but you can place it in a small rod tube if you want to take it along for the ride. Great for wall mounting too. Bill Covington uses this chart a lot.