Being a Good Sam member, I mostly try to stop at Pilot/Flying J to get the 8 cents/gallon discount on diesel. Checking on Pilot/FlyingJ website I found on their "locations" page this option for All Locations:
https://pilotflyingj.com/store-locations/ Click on the Download Locations and you can download all their locations information int .csv or Excel format. You can filter on stores that have RV lanes. I found that out of 683 locations only 187 have RV Lanes and they are not always where I need them when I need fuel. I DID use one just east of Columbus, OH and I happened to need propane, too, which was right there, but on the wrong side of my RV. I had to go all the way around their parking lot and pull thru the RV Lane the opposite direction, so they could fill the propane. It wasn't that big a deal, but it took some time.
Since I am towing, I am leery of trying the outside lanes of the auto section, because there usually is not enough room to swing wide with the toad. It is just easier to go to the truck lanes. If I need DEF, it's right there, too. I have used a credit card and Good Sam card for the $.08 discount with no problems. I rarely get a printed receipt, but I write down the details on a note pad, anyway.
Just be respectful of other drivers and pull forward after fueling, if you need to run inside for food or drink.
The one chain I dislike is Love's. They never have RV Lanes and you always have to go inside to have them pre-authorize your card (I usually go for $70) before you pump. They actually only charge your card for the actual purchase amount, not the $70.
For interstates, I use the app
"iExit Trucks". It locates you on the interstate and which direction. You then can see truck stops ahead and what restaurant they have. You can tap on a truck stop to see details, then "View on Map" (Google or Apple) and then go to satellite view and see the layout of the station.
For non-interstates, I use
Gas Buddy to find Diesel nearby.
One caveat, Road Ranger truck stops have Pilot diesel fuel, but they don't honor the Good Sam fuel discounts.