We just unhook the ladder from it's "secure" locations on our globe trotter and place a cot down for Drew. We then wedge the base against the top of the cot and against the sidebox of the horizon. So far neither Mandy or I have fallen outta the GT nor have we killed Drew.. He's only 72lbs soaking wet and I'm hovering around 200, so it can hold some weight. We've done it in the deserts of AZ, Mtns of New Mexico and other locations.
The cot goes against the outter door and fills the base of the GT pretty well. So we have to scamper down in the AM, but he's slept through it a few times.
Not sure I'd want to carry another "item" to hook up onto the trailer. The shower, sink, stove, chairs, and such take up enough time.
I can shoot pics if your interested this weekend. I should be off this one..