Flights from Sydney either go Straight to Vancouver or land in LA or SanFran, then connect to Vancouver. If you were to stop in Portland on your way you could go to the Gorge. They have websites with cam showing local kiting conditions. Is a prime location but bring your steamer cause it is cold.
Guys kite in BC too, though I'm not sure how far from Vancouver. My guess is BC, Seattle, or Gorge would be way better for wind than LA. Probably a little colder, though July should be okay (most guys in the Columbia are in shorty's by then.)
Here in Vancouver in July we have very reliable flat water kiting at Squamish. Kite size is almost always 12m and the wind is steady. There are usually at least ten of us on the water on any day. Squamish is a one hour drive north of Vancouver.
We have other places too, but Squamish has good wind almost every day in the summer.