Excellent episode. It was nice to just focus on a few characters for a change. And it was also nice to see Michonne act and speak somewhat normally. That was a very pleasant change and a dramatic improvement for the character.
My one minor quibble is that if the prison is only five or so hours away from Rick's hometown, possibly less if there weren't any traffic issues with car crashes blocking roads, then how did Rick not know that the prison existed? Surely it would have been one of the closest ones and as the local sheriff, Rick would have at least been aware of its existence?
Ignoring the hitchhiker also seemed odd when 100 guns are useless unless Rick has 100 people to use them in defence of the prison. Sure, Rick and his group have had some terrible experiences with strangers, but if they want to survive, the group needs to expand. That typed, I don't know how useful the hitchhiker would have been since he wasn't even carrying a weapon to defend himself and instead chose to walk along with pots/pans making enough noise to attract plenty of walkers which suggests that he initially adopted a survivalist approach to the outbreak and has only recently emerged for food.