Look at the nerf bars/side steps if equipped. Look underside for scratches and dents. Make sure the supports come out at 90 degrees from the frame. This will help tell you if the vehicle has been offroaded. And if you want a set of nerf bars with an offroad scratch and dent, you can just buy mine.

 

Thanks guys, this is all excellent info!
Thanks for the offer importkiller but being as nice as your H3 is, I'm sure I couldn't afford it!
TC