What about Wacamaw River Tours. Make your reservation, get there early, stand at the gate and get a seat in the front row. They cover a lot of beautiful areas (also ICW). At one time they did private cruises in a smaller pontoon boat. They were also on Groupon about a year ago.
I have looked into the tours and its a possibility, but I am the kind of person who likes to control their own adventure if you get what I'm saying.