Olympic National Park in Washington State is just one of the National Park Foundation's featured "Romantic Getaways". Crater Lake in Oregon is not listed but worth a look as well!
From nationalparks.org:
"What could be more romantic than looking out at the tranquil waves rolling onto the pristine beaches of Virgin Islands National Park? What could be more awe-inspiring than staring up at the brilliance of a clear, endless, starlit sky at Rocky Mountain National Park?
Get creative, get adventurous, and get a copy of the latest edition of our Owner’s Guide, “I Heart Parks!” The new FREE guide is filled with ideas and inspiration on what to do and see at 15 of the most picturesque parks across the country. “I Heart Parks” is chock-full of tips and advice for any type of trip you and your love hope to plan. Whether you prefer exploring a national park within city-limits, or venturing out to conquer trails in a more rustic setting, we’ve got some exciting ideas to spark your imagination.
Rekindle the romance by creating a new memory. Strengthen your bond by conquering a new challenge. Celebrate your love by reconnecting to each other within the natural and man-made wonders of this beautiful nation.
You’ll be sure to impress your park lover with these fantastic getaway ideas! So what are you waiting for? Download the new guide today!"
There are wonderful national parks close to the Portland, Oregon area that might be great for your proposal, elopement, wedding or honeymoon, or just a romantic getaway. Visit nps.gov and nationalparks.org for more information.