I have the same van and love it. I played around with solar for mine and found it best not to have panels mounted on top because you have to be in the sun to charge them while I prefer to be parked in the shade. Better option for me was to have a portable solar system with long cables, but it didn’t collect as much power.
Discussion
I remember this from a few years back. Not sure how it would manage off road, but novel idea nonetheless!