You refer to east-west roads out of Quincy. Are you speaking of Hwy 28 toward Spokane, which eventually rejoins US 2? Even if bikes were allowed on interstates (they aren't here in MN), I don't think Id be comfortable on I-90. But I like the idea of going from Wenatchee to Quincy then headed east from there to Spokane.
Ultimately, I will be ending up in Glacier National Park to stay with a friend, so any advice on the Spokane to Glacier route from any of you would be welcomed, too. I can put up a separate post for that, too.