You can only make a reservation in person at the office at the park.
The launches are great; concrete, wide, gentle slope, plenty of parking.
If you camp, the raccoons will do anything to get to your ice chest. If you leave camp with no one there they will tear into a tent to plunder it's contents and they will jump onto your car to see what's inside.
Check the tides for the pass and the lagoon. An onshore wind near sunset is very dramatic and can reach a sustained 20 mph for an hour or so.