Though Misty states she did not leave the trailer, her manner of speach indicates she was not there the evening Haleigh disappeared:
Misty Croslin, the 17-year-old girlfriend of the missing girl's father, told CBS' The Early Show in an exclusive interview said Haleigh Cummings was asleep just four feet away from her the night she disappeared. "She wasn't there when I woke up," Croslin said.
Her verbal recant of events insinuates she woke up elsewhere, came home, she wasn't there.
If she had been in the trailer, her recall would put the sequence as follows: I woke up and she was not there.
It is just the way our mind puts things in a sequence of events as we speak.