I've got a 2016 Fleetwood Excursion and the DEF fill is on the passenger side. When pulling into truck stops the DEF fill is always on the driver side. I've seen that people will pull in the opposite ...
That's an idea. Not sure if you have the same problem as I with the inset tank, but I need to find a long neck jug to fill up DEF from the pump. I have long neck funnels but hard to keep from spilling.