If you are going to be in the area during the 4th, make sure and visit the Seaside, OR area for fireworks on the beach. If you go slightly north into Gearhart, you can find a beach entrance to drive onto the beach (can't head south into Seaside area though) where you can watch fireworks. The furthest south beach entrance in that immediate area is directly on the west side of the Gearhart golf course. Look for the street with Gearhart builders Supply store to get back in the correct area.
The OR state park is interesting which is the north western most point of OR where there is a lookout platform... overlooks the ocean and Columbia River Bar (the graveyard of the Pacific). In the same general area, you can see the remnants of the Iredale shipwreck and also walk up to it, tide dependent. There is also a WWII battery you can visit where it is noted the only place on the west coast that was "attacked" during WWII. Definitely some history there.
Make sure and have rain gear and plenty of warm cloths. Be prepared for it to be rainy, cold and windy but hopefully you will get some nice weather.