A link in the latest PassageMaker Magazine points us to cruisersnet.net. This is a great site by Claiborne Young who has amassed a huge amount of information about cruising in the Southeast United States.
Of particular interest is the set of (free download) ICW Problem Videos. Covering "problem stretches", they suggest alternatives or good routes around some of the hazard areas.
Lastly, they have a page showing how a 80′ masted vessel has been making it down the ICW (Intra Coastal Waterway). They have some heavy (2000lbs heavy) bags of water hung from the mast tops. They let them heel them over until the mast will clear the bridges. Check the pictures… you’ve got to see this to appreciate it.