i suppose my real question is, on what continent does the infection originate and in what area?
i would attempt to access an island far enough from any large shore-or situated in any body of water deep enough to thwart any zombie advances. if you think about it, a continental shelf would be impregnable. it's far too steep for the poorly uncoordinated masses and the amount of time spent in the water would surely disintegrate their rotting flesh.
at this island (preferably small and deserted), once you have established lookouts (for other bands of the uninfected) we could set up quarantines and physical inspections for prospective colonists.
From there, with survival being the top priority you could declare temporary dictatorship to the most intelligent colonist.
Necessary barricades would be erected along beaches that aren't guarded as a backup plan, although, they shouldn't be needed. if this area is far enough from the mainland, there is a possibility that the zombies might not even know of the colony. from this point, more permanent political and economic solutions could be developed-ideally with a very similar government to that of America, although on a much smaller scale.