Hi, would like some advice please!

My wife and I would like to take a road trip from Seattle to San Francisco this July/August. Hoping to take somewhere around 5 (driving) days to make the trip, cos we're travelling with our 3 year old son we don't want overly long sit downs in the car.

We've got a few days extra, so also thinking about slotting in a day or two maybe to visit Rainier, or a theme park around the Portland/Salem area.

Any advice on where to have our stops? In particular I'm concerned about the 8hr drive between the Oregon coast (which we were thinking about doing on the 101 instead of I5) and Napa Valley.

Thanks!