While Rick, Hershel and Carl drive away from the attacked farm, Hershel is still watching his occupied farm from the car's back window. Doing so, he should easily notice Andrea running toward the car while they were escaping the farm.
When the truck stops after Lori threatens to jump you can clearly see that the shots inside show there is a turning just behind the truck. However the long shot of it turning round has them on a straight road with no turnings.
When Daryl returns to the farm to get Carol, you can see his motorcycle has 'offroad' tires, especially noticeable by the large MTX style tread pattern on the front wheel.
In later scenes, on the highway meeting point and when they pull over when Rick runs out of gas, he suddenly has 'road' tires with a significantly different tread pattern.
When Hershel is reloading his shotgun, a walker approaches him from behind. Suddenly, Rick shows up and shoots the walker just behind Hershel's head. Firing a gun from that close to someones ears should make him/her unable of hearing anything at least for a few minutes. But immediately after that, Hershel hears and answers Rick's question easily.