Enjoy the road trip. I did that a few years back, LA to Whistler. 1 month trip.
It will be easier for you since from SF to Portland is 7 hours closer.
I will be doing another road trip this summer from LA to Seattle.
Since you have a 10 years old, here are what to do in Seattle that you need to book.
- Boeing Factory Tour
- Space Needle (Book for lunch or dinner, I was lucky that there was an opening when I was there. They said usually need to book a few months out).
I was trying to drive fast, but after a few hours of driving, I did my math.
Going 90mph or 80mph, won't save me that much time. If I get pull over, it will actually cost me more time.
I just follow the traffic and try to stay on the right lane.
Have fun and be safe.