The crossings from Washington State into Canada are all well-developed highways; but we see them entering Canada on a narrow road with no center line.
The geography of their trip north from Portland is mixed up. We see them in the red truck with Leon and Harry, at Britannia Beach, some 70 miles into Canada. (The give-away is the mining building behind them, which is distinctively Britannia Beach, BC.) Later, with 66, they are south of Seattle, deciding where to enter Canada. Then they are obviously in White Rock, BC, again looking at a map to choose their route into Canada. (White Rock is just across the border, in Canada, and 70 miles south of Britannia Beach.)