Post office Lake is down off Lower River Rd. Its almost to the end. It was dry this last year and is not really a fishing lake. It has a small stream that runs in to the columbia River on the West end.
As far a Panfish this time of year it gets real slow. The Crappie are thick in Streets channel at Silver lake. There are a few small perch in the Woodland bottoms. And Kress has them all , but with the cold water it's really slow.
Muthnomah channel is also a good bet, but you need an Oregon lic.