1. a passage, as through a continuous row of houses, permitting access from the street to backyards, garages, etc.
2. a narrow back street.
Even by the definition you used, none of those paths were "blind alleys".
As to getting out of his truck to look at a street sign, all that means is that he never paid attention to the names of the streets. It does not mean that he was lost. Being lost means that you do not know how to find your way to a destination from where you are. Zimmerman knew where he was, but as he was talking to dispatch he realized that someone not as familiar with the neighborhood would not be able to find him with the information he could give them at the moment. Your argument about him being lost would apply to me looking up google maps to give my wife directions from my house to work because I knew that she would not know the things I could think of off the top of my head to describe where to turn.
Furthermore, my comment on the preponderance of evidence was not based on what was found in court, but in what I was able to obtain by looking at various sources. The evidence in the Zimmerman case overwhelmingly failed to support a different story than the one he gave. I am not saying that it overwhelmingly supported his story, merely that there was little or no evidence that actually supported a different story. (There is a difference between not supporting an account and contradicting an account).