It can get busy down there. Especially right now that the coho are coming home. The two best fishing spots are just below the hatchery and right at the mouth. So, lots of guys wanting to fish the mouth are walking down the path past the ponds to get to the fishing hole.
You wouldn't need a blind. The grass is pretty tall, could just sit in some of the clumps of grass. Would need a WDFW pass or Discover pass.
There are ponds and small lakes scattered around the county that get birds, but seems like they don't get lots of birds like the coastal marshes or flooded fields do.