I'm not familiar with Lake Wilhelm.
But Kettle Creek Lake is a beautiful lake in a beautiful location.
And there is state park camping very close to it.
I drove by there near dusk on Labor Day, after the crowds were gone, and it was so quiet and peaceful there.
There was just one boat out on the lake, with 2 guys fishing.
I've heard that it's good for panfish. It's also stocked with trout, but I don't know how many survive the summer. There are smallmouth bass in Kettle Creek above the lake, so they may be in the lake also.
Elk are often seen in the flat floodplain areas above the lake.
In September it's quiet in that area. The summer crowds have thinned out because school has started. And hunting seasons haven't started yet.
From the lake, it's a short drive up to a scenic overlook over the lake and the valley. It's a great view, and it's very enjoyable to sit up there and eat your lunch.