Man, you are in for a treat. I used to live up in Bellingham and I live in Hood river every summer. You are going to be doing some serious year round boating. Rain all winter means lowland rivers/creeks are pumping, snow all winter means summer runs are pumping.
Here is my hitlist for you:
Wenatchee III out of Leavenworth big and fun
Icycle Creek Canyon IV technical narrow fast
Skykomish IV on the other side of the pass
Yakima - pretty cruise
Naches - don't know much
Wind River IV - awesome runs into late june souther WA
White Salmon IV - runs all summer think gorge games near hood river
Klickitat - runs most of summer easy II with one nice III
Deschutes - Harpham flats to Sandy beach one weak IV a few III great playspots and warm water, it is Oregon though
Clackamas - norther oregon good during May/June III to IV
White River - best continuous class III ever during peak snowmelt off of Mt. Hood
Hope this helps, I will be up in Hood River starting June 6th and kayaking a few days a week. Contact me for beta on the Northwest. I am not a hardman but I do now some good areas.