Extremely over crowded in the summer. The park closes daily very early as it hits capacity. The best times to go are winter, spring, and fall. Lights on the Bay is a great Christmas light drive thru that's over a mile long. Great host for the polar bear plunge.
Great trails for hiking. Beautiful views of the river. After a snow melt or a rain be prepared for saturated or flooded trails. If you're lucky you can see the otters playing in the winter.
Plenty of places to explore. Several trails to walk or bike. Be prepared for the bugs depending on the season. Some years we've had no issues, some years the flies were bad. The mosquitos are kept at bay with bug spray are citronella candles. The closer to the ocean the better you are. Definitely bring a canopy as obviously there is no shade Oceanside. The Ponies are giant trash pandas. They're smart and can open latches so do bring bungee cords, kayak straps, or ratchet straps to lock all of your food in cases or coolers. Check out the awesome views on the bayside trails. There is an app you can use to identify the ponies. The showers are cold but at least there is running water. Bathrooms are mostly clean and just a short walk from most campsites. Each site has a picnic table and fire pit. After dusk you can do beach fires as long as they're below the high tide line so they wash out.