[jime57]

Front undertray is worthwhile, but since you have a Camray you probably already have an effective one. Grill blocks on average report about 3%, but in LA you probably can't use much blocking. Mirror deletions have shown an average improvement of around 3%, but it would be suicidal to delete any mirrors in LA traffic.

In your situation, I'd vote for max sidewall tire pressures, driving as slow as you can without getting run over, and general application of hypermiling techniques. Coasting ICE-off and shutting engine off at long lights make a big improvement. (I have ignored Toyota's warning about coasting automatics for a number of years now, with no ill effects - your experience might differ. Be aware that if you shut the engine off, you only have one or two power brake applications available before the pressure is depleted, and you will have to steer without power assist. Try it in a parking lot first.) On your longer flat sections, cruise control will probably help. As I recall, many or the roads a pretty flat.

Replacing your car with a Prius, tailor made for this type of driving, would make a big difference, but would take a long time to offset the cost ;-)