Equine sleepover
The difficulty with fleshing out the context of this particular sentence is that there are so many variables. I feel as if we need to DM Susan and ask her what tone the line was said in, who was saying it, and who were they saying it to? As cute as the accompanying picture is, I can’t imagine there were children involved.
So, was it an annoyed wife suggesting that if her husband carried on arguing he was going to end up sleeping in the trailer? Or do these two have some sort of equine business and someone needs to look after a sick horse? Or maybe their house is being renovated and they have to choose between the car or the horse trailer. See, too many variables.