Before any trip to unfamiliar areas I plan what roads/hwys I will take. I then calculate my fuel stop distances. I then search fuel stations in the closest town/area. Once armed with the stations addresses you can use google maps to look at a street view. I write down a list of usable stops to take with us. This method has not failed us yet. I often can identify 2 or more in a given area so I have options. I started this practice because diesel access can be problematic on 2 lane hwys. It should be easier to find options this way for a gasser. I have surprisingly found some rather small stations that had an RV friendly layout.
Greg