Richard- thanks for your comments on the coast, etc. We had a great trip driving from San Diego to San Francisco, over to Yosemite, and back to LA. The only concern we had was attaching the infant seat to that third anchor point. It just wasn't working well for us.
Coincidentally, we met quite a few folks from 'down under' during our trip. All very friendly and fun-loving people. Some were hung up in airports and hotels due to strike by the airline, with no options for alternate flights.