Freelanceing,
Just looked on Gas Buddy and diesel at the GH Meijer and Walmart and it's presently $3.59 and you get it for $3.54 for premimum diesel with having a Meijer credit card. Same for Walmart with a Walmart credit card but it not the premium grade there. Meijer diesel is Marathon and Walmart is Murphy FYI.
Might you be talking about Spinners Corner at $3.89?
Same price we paid 2 Sunday's ago when we left for our trip. Gas was just under $3.50 then and it's constantly up and down like a yo yo but the diesel price seldom changes.
I do not know what mileage you get with your 5.3 but the diesel should get you a lot more than 20% better mpg's. Everything being equal as in load and driving actions, we always gpt 40% to 60% higher mpg with our diesel trucks over our gas engined trucks. All were GM except for the 2003 Ford 6.0 abomination that just love the service bay. Either gas or diesel will handle the load you said you would have going to Alaska etc.