I wish there was an easy way to remove them like on the 2dr. I would make a plywood platform with a mattress for camping.
I still sleep in mine with the back seats in. Run the front seats all the way forward and lean them forward. When you do this, the headrests on the folded back seats will drop flat. I use a piece of 1/4 plywood to cover the gaps left when you fold the back and sleep with my head to the front. You're feet angle toward the middle of the tailgate a little, but it sleeps just fine.
Oh, and I'm 6' tall.
2012 JKUR, LOD Mid Width Front Bumper
Warn M8000 winch, Modified stock Rubicon sliders
Teraflex 2.5" coil lift, Pull Pal
FJ Cruiser roof mod (painted white)