After I bought my '05 TJR, while going through the engine bay getting to know it, I found a extra key hanging by a piece of bailing wire next to the radiator. I haven't decided if I want to hide a key in the jeep anywhere at this point.
I had a spare key in a magnet holder stuck way up in the engine bay of one of my cars. You had to know where to look.
Now all my cars open when the key is in range and you pull the handle. Except the Jeep. But I unzipped the rear window when I forgot my keys in the ignition and "locked myself out". I did need to use my umbrella to push the lock button from across the jeep.