I understand MPG is not why anyone gets a bigger truck with a diesel. You can buy a lot of fuel with that $9k additional diesel premium.
My #1 reason for the bigger truck is safety in pulling my 7k camper and the truck loaded down with people and gear. The #2 reason for diesel is, It sure will be nice to make the 2k mile trip without having to watch you guys with the bigger truck and bigger trailer combo passing me like I'm sitting still. ? LOL