Directly contradicted by other source, which says that DW left not in the MH, but in another vehicle to go to the MH which was stored 20 miles away or so. His departure for the MH location came at about the same time Danielle was first feared missing, but clearly he was unaware of it at the time he left the neighborhood...all parties stipulate to that.
If she had gone out to play, it would then be debatable whether he had gone, might well have, before she came out....