Ah man that really sucks.. poor dog ! I hope he finds his way back home or at least somewhere to a person that will be able to notify they have found your dog. I've had a similar situation with a cat, only one day before moving to the other side of the city. The cat was just a few months used to this house (because I got her only that period) and then she escaped the day before moving. So we were all busy packing and loading, just with the last ride she found her way back home, to dive into the attic and was hard to get her. But was so glad she went with us. But cats have a good sense of finding their way back home I've heard. I keep my fingers crossed for you !