Joe,
I have driven that route east of the Cascades in winter, and if there is not any significant compact snow and ice to deal with, it is a good route. Pay attention to the weather a couple days before you leave to make sure there are no big systems predicted.
Also, avoid the Columbia River Gorge between Hood River/The Dalles and Portland if there is any chance of freezing rain. That corridor regularly gets nailed in winter, as interior air (i.e., very cold air) slides westward under an advancing warm, moist air mass which is the forerunner of a wet, warmer system. Many times, returning from eastern WA/OR to Astoria, I have elected to go up and around Mt. Hood on Hwy 35/26 to avoid the Gorge. It can be really nasty.
The other bugaboo is Snoqualmie Pass, when a snowy system hits that part of the NW. Listen on the radio for warnings and reroute in Oregon if it seems Seattle is getting snow.