Even though diesel is higher than unleaded, you might find that it is more economical than gas especially while towing.
My 1999 F250 Powerstroke 7.3 maintains 18.5-20 mpg highway unloaded terrain dependent. Pulling our 11,500 lb fifth wheel is around 12 mpg. Beat that with a gas.
My alternate drive is a 2003 suburban with the 5.3 liter. It is actually cheaper for me to drive the diesel than the suburban. I have to fill the suburban up every week - 30 gallons of regular vs the diesel 25 gallons every 2 weeks same miles driven.
The diesel cost is higher, but I have 176,000 miles on the diesel and it is almost broke in.
Anygunanywhere