Alright, just watched the Talking Dead from last night. Saw the preview of next week's episode with the guys banging on the bar door and asking if anyone is in there, that they're looking for their friends. So that does answer the question about whether they were alone or not. What that does not answer, and is going to be interesting to find out next week, is are they a group similar to Rick and the rest, or are a roving gang of guys and other people out stealing/killing/whatever as they come across people or stuff?
Based on the guy behind the bar reaching for his pistol, I'm leaning towards them being a gang of people going from place to place, city to city killing people, stealing their supplies, etc. If shit this happened in real life, it's not going all peaches and cream like it is with Rick and the group. There are going to be gangs and groups going around stealing, robbing, murdering, etc, just like there are in everyday natural disasters.