We fill up the available camping area at Grouse Lake. We even pull the rigs into the brush to keep the open areas for tents. If we have two groups there it will be a problem, but we always run that risk.
There is also camping at Swamp Lake, which is over the hill from Grouse Lake, and a good sized camping spot at the meadow before coming to Swamp Lake (a cabin and large picnic table mark the spot). If you run the trail from north to south you'll come to Swamp Lake first, if you run from south to north you'll come to Grouse Lake first. If enough of our group is interested in running Bald Mtn on the way out, we'll run it south to north.
We don't camp at the trailhead, we camp at Dinkey Creek. That is about a 20 minute drive from the southern trailhead and about an hour drive to the northern trailhead. We don't camp in the Dinkey Creek campground, we camp in the trees next to the road just past Camp Fresno. There is all kinds of room where we camp, no way to fill it up.