I've hunted the river end before for teal but never for big ducks. It was a good hunt and not a lot of pressure. Most all lakes in Kansas are up above conservation this year. Some of the boat ramps might not be accessible. Check ksoutdoors.com for water levels. Could be some good areas with flooded timber. Glen Elder is one of the largest lakes in the state so there are a lot of acres of water. I would try to get up a day early at least and scout the west end.