I don't think there is a viable alternative. Yes, going 205 in OR is better than I5, and only takes a little longer. Definitely 405 in WA, but it can have lots of traffic. Best to plan your route around rush hour times, in WA that's 6AM to 7PM, but at some point you just have to be OK driving slow here and there. I drive these routes all the time some with and many without a trailer. The OR drive is not that bad unless you hit it right at peak travel times. 405 in WA is always bad, but just hit and miss as to where. These days traffic is all day long vs a set rush hour. Just go and take your time.
