They took a road trip.

One thing for me is that the end of the mid season finale had Morgan finding the map in the church with the note to Rick on it. You have to think at some point they are going to give him more of a role than walking through the woods for 30 seconds twice a season. If he is going to join the rest of them at some point in the future he better hotwire a car and siphon some gas. He has some catching up to do.