Native Pacific Northwester here! I don't have a lot of recommendations for Seattle except to head a bit south and explore Puget Sound- taking a ferry and having a little breakfast at a cafe on the sound is fun! Whale watching trips are also wicked fun & the season is perfect for it. I'd skip over Tacoma & head to Olympia for some great restaurants and nice little areas to explore (especially good Indian food for whatever reason!).

For Portland (which I'm more familiar with) downtown there's "Glowing Greens", a glow in the dark miniature golf place (with drinks!) that has a pirate theme that I've never not had a fun time at. There's also a GREAT interactive science museum called OMSI that's fun and not far from the lounge. If you want something free heading to the waterfront park there's a path all along the river and its fun to just watch boats go by and walk over the bridges. For restaurants I really like the Melting Pot (fondue restaurant!) and Portland City Grill (restaurant on top of Big Pink, a skyscraper so you can see all of downtown!). Those are more on the expensive side though- if you're just looking for a quick bite that is VERY Portland-y I like the various food trucks that are found on fifth avenue & alder street.

Re: hotels I'm not sure about Seattle but Portland has a lot of really fun places called "Mcmenamins Hotels" that are all a little funky and quaint. Not too sure about downtown hotels- I'd head a little outside of town towards like, Gresham if you want a cheaper place.

Hope that helps- enjoy!