If you use diesel, most of us look for truck stops and use the truck fueling islands where the pumps are faster and probably have fresher diesel. The Pilot/Flying J stations are in a state of transition after the two merged, so they're still getting their act together and things may work differently in different states. On a recent trip they worked just like they used to, e.g. Jerry had to go inside to pay, but we used the truck islands and it did not cut off at $75. The reason is that our RV Frequent Fueler Advantage card was approved prior to using and they knew us. The pump showed an approved message after he swiped the card and before fueling.
Two companion books might help you, RVer's Friend and Trucker's Friend. They list by state gas and diesel stations that can handle large trucks and RVs. We carry both. The column that gives the number of truck parking spaces often is a good clue as to exactly how large they are and whether your size rig will fit. If it says parking for eight it's probably pretty small, but if it says 110 we know fitting won't be a problem.
Also, some of the RV fueling islands have car parking in front of the convenience store and you have to maneuver past the cars to get out. Sometimes it's a really tight fit. That's another reason most of us who use diesel use the truck islands.