This was our first U.S. National Park in the Pacific Northwest and it was awesome. If you can go, you must drive up the Hurricane Ridge. It is a bit of a drive, but it's absolutely gorgeous, and the views at the top are stunning. There's another visitor center at the top of Hurricane Ridge (where you probably will see deer and beautiful foliage) with park maps which describe the views and mountain ranges, including Mount Rainer the highest peak in Washington.
We drove from Seattle to Port Angeles for the night, and next drove to Forks so we could experience the Olympic National Park from the Hoh...another amazing highlight! It was definitely worth it to experience the national park from the different points and take two days of our trip to see this. There are lots of other sights to see on the Olympic Peninsula which we were also able to fit in on the road trip.
The Olympic National Park is massive and the Visitor Centers in Port Angeles, the top of Hurricane Ridge, and Hoh Rain Forest are great for the history and ecological lesson. We went the third week in July and the weather was amazing, sunny and warm everyday. Wildflowers were out in full bloom and there was still snow at the top. There are plenty of hiking trails throughout the park, which was great to get out an stretch our legs and take lots of photos.