I'm at the first optional town and have to get gas from ''Lucky's'' gas station. Once I get the codes and restart the generator a whole horde of walkers come and I'm directed to go back to the car.
I ran back (as I assume stealth is no longer an option) through the grocery store but I get to a doorway where I get surrounded and get into the ''grapple'' (aka can't move).scenario with an endless amount of walkers until I eventually die.
Once you started the generator you gotta get to the gas pumps, press X to fill, once 100% just sprint to the car. Just keep sprinting right and you'll see a highlighted area waiting there. I had the same problem only I kept going into the police station looking for an exit or something.