I'm not going to criticize the survivors of "The Walking Dead" too much. They've been through hell. They are obviously in traumatized in all sorts of ways. Still, their current strategy of survivor is pretty counter intuitive to their observations if they had time to think about things.
Here is what I've seen. The dead are a natural phenomena, that is they are bound by the rules of science and not magic. Though they are moving by some unknown means they are still dead. They are rotting. The ones in Atlanta, clearly first victims were often the ones least capable of complex movements. Obviously as time goes by rot is going to make further in roads in how dangerous the walking dead can be.
Therefore, driving around the country is probably not the best way to deal with this. They are bound to keep coming in contact with dead, and moreover more likely to find fresher walking dead away from the major areas of infection.
My suggestion would be to gather as many supplies as you can, specially water and find an isolated building of four or more stories high. Occupy the top level and destroy the stairs. Then just wait it out. Even if the walking dead are not rotting as fast as a normal corpse might, they are rotting. And even if new walking dead are created each "wave" will be smaller and smaller as there are less living. By all rights by next summer it should be safe to move around again for the most part.
Of course as drama that's not so exciting. So I can understand if the writers of the show want to keep everyone on the road.