I wouldn't make a special trip to get here but if you're in the area, it's definitely worth a look-see. Take a short hike along the beach with an unobstructed view of the Cook Inlet. At low tide, the feeling is almost eerie and desolate. There are great views of the Alaska Range.
At the end of the Park is a great picnic area with a nice view of Mt. Iliamna (an inactive volcano).
Stay on the beach proper! At low tide, it seems very inviting to walk out to the rocks but the mud is a very fine silt that can suck your feet in making it very hard to extract them. The tide is incredibly fast and many people have drowned making this mistake.
FYI: The Cook Inlet has the second fastest tide in the world (the Bay of Fundy is first).