If you're talking central/eastern Piedmont largemouth fishing, I can offer this ...
If you have a nice warm day or warming trend, I'd be targeting the sunny side of the river. Regardless of ambient conditions, I'm targeting the deepest and slowest moving water or shallow cover in areas adjacent to the deep water. A sunny flat next to a deep hole with some cover is a prime target on a warm day. Don't be afraid to cast into 12" of water in those conditions. Also remember that just because you can't see or map the bottom, doesn't mean that it's featureless. Most of the upper Cape Fear and Upper Neuse have great "deep" rock structure. Deep for these flows may only be 4-8'. Most of these areas will be in the main channel, but will also approach the bank on the outside bends above a shoal.
Pools below rapids and pushwater above rapids rarely ever produce for me in cold conditions. I think the flow is too swift and these fish are in energy conservation mode. Oxygen levels overall are great in winter, so they can go wherever they like. In my experience, they like the water to be slow and warm in winter. In spring/summer, aerated areas below rapids are prime targets for schooling baitfish and higher O2 levels.
If we're talking smallmouth flows, it's a little different.