Inland, and less frequented parks; maybe. Sure, Death Valley in July shouldn't be too much of a problem. The Coast, Wine Country, Major lakes, forget it. In some of the Coastal parks where reservations are not accepted groups have gotten together and exchanged cell phone number and e-mails, and they exchange sites between each other (I'm leaving tomorrow at 10am so get here at 9:30am and pull in when I pull out). Really. The State Park system is broken, but I neither an answer or the interest to make suggestions. I just head for the Private campgrounds, which along the Coast are still difficult to get unless you are real flexible with dates.