I practically came up with this like 5 minutes ago, so it's still in its VERY rough stages, but here is my idea: I was thinking about how Cars Land really doesn't fit in with the California theme at all, so I thought of an idea to connect the theme to it better. This would go on the Flo's Drive in Diner area. It would be a multi-story showbuilding (2 above ground, one underground.) The facade would display a "Radiator Springs Museum" that would "Showcase the Beauty and Wonders of our Town." The queue would wrap through the museum, with lots of interesting facts about Route 66 along the way. You would then board a ride vehicle(no idea what it would look like.) and you would be whisked off onto your journey into Route 66 history. It would start in the 1920s when Route 66 was started. They would tell about the original route of Route 66. I forget where it started but of course it ended in California. It would then go through a scene where people are migrating along Route 66 during the Dust Bowl. A lot of "Dirt" would be blowing in your face. A narrator would tell about how tough these times were and how many of those people migrated to California. It would then have a scene during WW2 and people are going on Route 66 to California to work on the many facilities they had there for WW2. The next scene would show how Route 66 aged and became replaced by the Interstate. The ending scene would show how Route 66's legacy lives on and all that stuff. One problem is the boredom factor. Pretty much ALL of California history is boring to people and is not what people want to do on their trip to a theme park. I think that is the reason why Imagineers went with all the attractions that LOOSELY fit the California theme.
Ooohhhhhhhhhh! I just came up with a better way to implement this! It would be placed in a more subtle way but would still show why Cars Land is in a California-themed park. They would have Flo's Diner built (themed to being a drive-in movie theater, of course.) The movie that would be showing while people are dining is a movie about Route 66 and how it ended in California. To make it more than just a movie they could have a few animatronics in the show and some live actors. Next to the dining area, there would be another area for people who aren't eating to watch. What do you think?