I try to make all my stops at Wally World where they have diesel. Not only is it cheaper than the freeway truck stops but I use their credit card which gets anywhere from 5-15 cents off/gal. That adds up in a hurry. We ran 3700 mi last month on a trip and several times the difference in truck stop and Walmart was 30-35 cents/gal.
I will admit they don't want big rigs at their pumps and designed them that way but by being creative I've managed to get in everywhere I wanted to without unhooking.
Wally World has an app for their store and you can specify w/fuel pumps. Gas Buddy works real well also. I also use Gas Buddy to see which side of the state line to fill up on. Missouri diesel is 40 cents/gal cheaper than Illinois for example, same brand station just on different sides of the Mississippi.
I usually drop off the DW at the door of the store to get any needed supplies and then fill up and go back and pick her up.
Now if they ever put the diesel pumps in the middle instead of on the end I'm in trouble.