Rules of the go pro....
Down low conveys speed an action. If you are wheeling, a gopro up top (like on the windshield frame) will minimize obstacles...meaning, you can run a decently knarly trail, but it will look like a parking lot if the camera is up high. So, if you want action and speed (like running in the sand dunes) keep the camera low. If you are trying to show the scale of a trail (like black bear pass) you want it as high as possible. Speed you want to add if you are doing a rough trail where you are doing 5mph, but that gets boring to watch, so putting the camera down low will make it LOOK like you are going a lot faster.
If you want to make a movie, you need to get a bunch of shots from both angles, front and rear. If you want to add drama (ie a shelf road), mount the camera on the side of the jeep (the side that is facing the danger) and shoot that way, with a slightly downward angle.
Another awesome place for a gopro is usually behind the front tire (shows the action of the tire) but on the wrangler that isn't easy due to the wide flares.
Also, shoot in R3 (720p at 60fps.) Makes for awesome slowmo, and the wide aspect adds drama.