Several weeks ago you asked the same question--we all had our own opinions about the border crossing but the consensus was that you should leave as early as possible in order to deal with any potential problems that may arise at the border. As it is, its going to take you around 2.5- 3 hours to get to the border from the Airport area. If you want to be at the Ferry terminal by noon, I'd leave the hotel at 6 am. Yes, I said AM! That way you will have no worries about making the boat under almost any circumstances, and if you arrive early there is plenty to do, and plenty of places to eat, and your kids can sleep in the car.

I always cross off I-5, its the only route I know of and you cannot miss it if you take the freeway.

Don't forget binoculars! Have a great trip, Amelia in Los Angeles