They're up a little higher than most might want to mount them, but I'm a tall guy and don't mind it. Plus this way I think they're less prone to be kicked or damaged.
On the side of the garage I had an existing, structural 4x6 that I doubled up just to push it further away from the wall (although it doesn't hurt to have the extra peace of mind in strength). I then bolted 2x4s on either side where the loops would bolt on for the hinges. These were all held in place with 3" lag bolts and washers.
The opposite side is held on by an old bicycle hook that I cut down to size. Fits perfectly and the door latches on just like it would on the TJ. (Note: it helps to pull the plastic coating back as it is a little too snug with it on there).
I measured the distance between the hinges on the door and spaced the 2x4s for the bottom accordingly. I think I came up with about 12 7/8".
I just attached these loops with two 2" screws each. Seems plenty strong enough to me after how many times I had the doors on and off just for fitting purposes.
The loops were just old gate latches that I had lying around that I expanded around a 7/16" drill bit which gave me plenty of room to wrap them in electrical tape to somewhat save the paint.
After hanging the door on the loops I could get a good idea of where to screw in the modified (hacked) bicycle hook.
I did the same thing on both sides, although the boards I screwed into are a little different to accommodate each door.
All of this was built from scraps I had lying around the house and therefore "free." Now I've just gotta work on a place to store my windows and frames. Hope this helps anybody else! Criticize away!
Sent from my turtle in a half shell.