Hi Bryan,
Can't help with a JK. I have a JKU, and built an aluminum raised platform after removing the rear seats. This provides room to stuff gear and supplies under the floor, and sleeping/dog room on top.
The big arsed fridge limits it to the dog & I though. A smaller fridge would allow hinging a panel above it, so the whole back of the Jeep would be flat. That would make a decent bed for two.
Pic #1 is the platform
Pic #2 and #3 are camping up in Plumas National Forest a couple of weeks before the first snow of the year, and then right after the first snow.
Pic 2 shows rocks under rear tires to level out the Jeep. Worked great.
Picture 4 & 5 is all the gear and supplies loaded up.