I liked last nights episode. A good season premiere that set everything up well and filled you in on what's been going on like every season premiere should do.
The scene in the store was really cool. It was funny when a couple of the zombies feel to the ground and their heads went splat right away.
I'm not sure what the point of Rick meeting that woman in the woods was? Maybe they just did it to creep us out a bit or to show how far gone someone can mentally go in this world when they've got nothing left. It may have been a better story if Rick took her back to the prison and helped her get healthy again.
With Waldo dying at the end and turning, i'm guessing since everyone is asleep, he will get a few people before anybody knows what's going on. He also coughed into that big tub of water before he died, so whatever he died from could be contagious and infect more people in the prison.