I think by that rate would actually eventually clear out enough land to set up a land base community, it'd be a good trading outpost and make getting supplies to secure areas much quicker. With enough man power, fencing in sections of a town or city wouldn't be hard, and stationed guards would be an easy peasey job! Not like zombies move too awful fast, but we'd be more weary of other living humans... nasty species we are.
Besides we'll need land based connections in the future, hurricanes can be quite a nasty thing and I sure wouldn't want to get stuck in a giant boat during one. O_O