Just a side note to all that's going on here.
My fuel economy has improved by approximately 1.8MPG.
The only thing I can think of is the quality and type of gasoline going into the tank.
Most of the pumps here, and all of the pumps we refueled at during the trip, have the disclaimer "May Contain Up To 10% Ethanol" on them, so it's not like I'm getting 100% gasoline all of a sudden.
I've read in reputable publications for 20 years or more that gasoline in Kalifornia is very strictly regulated, and blended quite differently than that sold in other states.
Either Kalifornia uses some zombie-blend that kills fuel economy, or the 1100 mile trip pulling a dual-axle trailer really loosened up my engine!