The combined EPA rating of 43 mpg for the Touring suggests you can not only make 400 miles but have about a 100 mile reserve. Tank size on all HEV trims is 11.9 gallons. Much will depend on your driving style and weather conditions. I can tell you about my experience so far with the LX:
First tank 496 miles on fumes, 42 mpg, driving 70 on the interstate in really cold weather.
Second tank 556 miles (15 miles estimated left by car), 48.5 mpg, driving slower but still around the freezing point.
Third tank, about 300 miles at estimated 49 mpg still driving slowly but above freezing. Estimated range by car is total 590.
I'm expecting 600 plus will be easy in the summertime. All fill ups were topped off, and the mpg was calculated, not estimated by car (my experience so far is car estimation is 2 mpg optimistic). Hope that is helpful. There is a learning curve on how to get the best mpg and I still have a ways to go.
2018 Kia LX HEV Metal Stream with Advanced Tech