Spending three nights in Port Angeles gives you a two full days to explore the park as well as your two travel days from and back to Seattle. You might try at least one of the longer hikes at Cape Alava, in the Hoh Rain Forest or at Sol Duc Falls as well some of the many shorter hikes and sites to see. You will definitely want to see Hurricane Ridge, but with more time, you might also climb Klahane Ridge for a hard climb with a spectacular payoff or hike the Spruce Railroad Trail and enjoy the great views of Lake Crescent. You might also want to visit the Kaleberg website or use some alternate resource to discover other hikes and local treasures.