In the TJ I was most comfortable sleeping in the front seat reclined. I tried to figure out the back but never was comfortable enough. Someone once said if you put the passenger seat all the way forward and removed the rear seat, you could put a board of plywood in to even it out a bit and then an air mattress over it. I never went that far.
2013 JKU Sport, billet, auto, 3.73, LSD, 315/75/16 Duratracs on MB 72, 10A springs, Bushwacker flatties
Sold - 2005 TJ, red, auto, 3.73, 33" Duratracs, 4" lift
Ice storm casualty in 2007 - 2003 TJ, green, auto, 3.73, 33" Duratracs, 4" lift