Still Creek is a very nice campground centrally located near Government Camp.  It is in close proximity to Trillium Lake and Timberline Lodge.  The sites are large and great for kids to spread out and run around.  Really only 2 negatives to this campground to be aware of: 

1)You can hear the highway, its not bad but definitely noticeable.

2. There are no speed limit signs on the road or in the campground.  Many people drive through the campground as a back way to Trillium Lake and they drive FAST unfortunately.  If you have kids this is a pretty big concern.