Just couple of variations of mounds of hardened dirt/mud that could be placed anywhere. For example placed in the simple grid map. Like dirt bike jumps except slightly different angle slopes on each side for variability. Maybe 10-20metres dia. by 1-5metre height (or any size really) For someone who can make vehicles/props, i imagine it would be quite simple? If the prop was made chaseable then the ai could be set to aim for it.