The Australian equivalent (same engine) shows 31mpg "Extra Urban" and 18mpg "Urban" with a 19 gal fuel tank. That seems like a big difference to me but could be entirely just on how different the testing cycles are between the US and Australia.
Regardless, with a 19gal fuel tank, with the US EPA numbers, range should be ~494 miles highway, 418 combined.
These numbers are better than the outgoing Sedona. Specifically, an improvement of "1 mpg in town and in combined driving, and 2 mpg for highway driving. This is made more impressive by the fact that the Carnival switches to a bigger, more powerful 3.5-liter V6. It makes 294 horsepower and 261 pound-feet of torque to the Sedona's 276 horsepower and 248 pound-feet."
I’m happy to see they aren’t doing auto start/stop technology on the new model too. Something that won’t have to be constantly deactivated every time in warmer TX weather. Interesting because the Telluride has this feature that most drivers dislike! So a win there!