the mileage difference is about 50 miles (Tacoma to PT). If the truck comes on I-80 (through Oregon and the Columbia Gorge) the mileage difference is about 25 miles. If they go on I-80, going to PT instead of Everett allows them to avoid Seattle which might make the actual time shorter since they could go off I-5 at Olympia and drive up the east side of Hood Canal. I don't think they would need any special permits for your boat, so the two lane roads are not a problem. Also, the ferries can handle full size semi trucks. Avoiding the ferry would save money