While in Seattle, check out the big ones like the Zoo, Science Museum, Aquarium, Pop Culture Museum, Space Needle, take the monorail around, check out Pike Place Market for some good seafood or get your wifey some fresh flowers. Take a drive up to Snowqualmie Pass and see the mountains. Take the Amtrak from Seattle to Leavenworth (which is like a bavarian tourist town in the mountains). Take a cruise on Lake Chelan and visit the tiny town of Stehekin (a good substitute for an Alaskan cruise!). Check out Mt. Rainier National Park. Take a drive over the Olympic National Park, or Bellingham and North Cascades National Park. Go check out the San Juan Islands. Drive over to Port Angeles and take the ferry to Victoria BC, Canada.

I'm sure a cruise up to Alaska would be breathtaking but there is totally plenty of gorgeous landscapes around Seattle to see that would save you 15K.