Currently closed (2017)
We stayed at Messenger Flats while hiking the PCT, only because you can camp anywhere within 20 ft and we wound up arriving at camp well past dark. We were surprised to find that the campground was closed but had clearly been used by hikers for the past season. We met a ranger the following day at a water cache not too far from the campground, and he told us that the entire national forest (except for the trail) was closed to camping due to fire damage from previous years.
The campground was a nice place to stop. When in full service, it has pit toilets, and each site has a picnic table. There's beautiful views of the ocean on clear days, we could even see the Channel Islands and the LA lights once the sun set hiking in.
I highly recommend staying here once it reopens. It's a great, pretty secluded campsite.