Thanks all for the helpful advice above. On a Tuesday around 10am, there was no wait to cross into the US. Later that evening around 7pm, there was a 5 minute wait to cross back into Canada. We did not have to get out of the car either time, just handed over our Aussie passports for inspection. Did get some aggressive questioning by the US officer but I guess this is the norm these days. All up from downtown Vancouver, it took a leisurely 2.5 hours to get to the Boeing factory at Everett. Driving back to Vancouver from Seattle, took just under 3 hours....no hassles whatsoever if anyone else is planning a similar trip@:-)