Your best shot at winter bass in Oregon are the South Coast lakes between North Bend and Florence. They typically have the warmest water in the state during the cold monthes. It will not be like it was in the summer with bass chasing down and trying to kill your lure. Bass, like all fish, are cold blooded creatures meaning that their metabolism slowes down considerably in cold water.
Water Temperature is Paramount!!!
Bass will be migrating on the vertical plane not the horizontal in cold water meaning that they will not be on shallow flats, but near deep drop-off areas.
If the water temperature is under 45, good luck. I have never caught a bass in water that cold.
46-50 degree water is slow and deep. The pickup of the bass will be so very faint that most people would not detect the bass even when he spits your lure out.
Low 50's puts bass on the first drop-off near the shallows with an occassional foray into the shallows in the warm afternoons. Fish a jig-n-pig at this time, or try a slow-rolling spinnerbait.
At 55, the bass up here get easier, and its all out fun past 60.
Winter bass usually are more active in the afternoons, so don't worry about getting to the lake early. 11-3 is optimum.
Fish the Northwest corner of the lake first. It warms up sooner because it gets the most sunlight.
Hope that helps a little. I'm waiting until early-March before I go bassin' again. The next two monthes I plan to fish for winter trout or early, deep perch.