Thanks!
I'll check out the I-90 route and see how much further (and/or hillier) it makes the route, I think we are getting close to our upper limit if since we would like to enjoy more than just cycling that day. But maybe start with the Burke-Gilman trail and decide where to go when we are at Redmond depending on how we feel.
What he expects to find? I don't know, I'm just happy to get company on ride!