The gas buddy app for android phone is a nice app but it doesn't show always that the station selling diesel is accessible without major headaches. (Way too many stations have the fuel lanes perpendicular to the road and if cars are parked in front of the station, it is almost impossible to get enough clearance to make the turn. Angled fuel lanes work much better.) We use it tho in conjunction with Fuel Book 3.0 (free app for android phones). Fuel Book lists truck stops only. You can generally get a picture of the station showing you the lay out. Someone mentioned using truck lanes and that is great advise everywhere but Indiana. In Indiana, the truck lanes are restricted to OTR truckers because of the way they do their fuel tax. That being said, they also have lanes marked auto diesel that works for RV use.