Boad River/cold River Fishing Tips?

If anyone is familiar with river systems, I would love any advice. I am fishing in Cherokee County mostly in what is considered to be Ninety Nine Island : backwaters from Broad river. I can catch fish while in the backwaters, but would really like to go up the main river channel. The main run is maybe 50-75 yards across and has a well defined channel and substantial current. I've read that largemouth shy away from the current while the water is cold. So, my question is; does the entire population migrate to the back waters or can they still be found in the actual river?