Pre-spawn in a muddy river can be tough. That's the bottom line. One thing to remember is that bass hate the current in the Wintertime. They don't want to exert a lot of energy, so they're gonna head away from the current. Current breaks in a river are always good if you wanna catch fish, but from my experience, rarely are there big fish around them. If your river has docks, concentrate on the ones that are near spawning coves or docks that are in deeper water, like the 6-12ft range. Skip a jig or senko under there and usually you'll catch big ones that way. If you have any points or other good structure, fish some of the deeper stuff. You can throw a football jig, deep diving crankbait, Carolina rig, etc.. If you have a lot of shoreline cover, flipping a Tx-rig or a jig in there will get you bigger bites. Try to find cover that's near deep water or in deep water, like timber along a channel. Sometimes there are logjams or brush piles right in the middle of nowhere, so use your electronics to kinda scan around. If there is a flat covered in stumps near a spawning cove, throwing a flat sided squarebill in a chartreuse/black back color can deadly for big fish. Be sure to fish slow and stay out of the current.
Hope this helps
"If people concentrated on the really important things in life, there'd be a shortage of fishing poles." - Doug Larson