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The place i would go to is one that no one would ever try: Inner city school. Think about what they look like, bars and wire on the window, solid steel doors and lots of helpful things inside.
My school had an electronics shop, a wood working shop, welding shop and a mechanics shop. Not to mention you have shower facilities, a kitchen to convert with a generator, a library to read in and a gym to work out in.
Turn on the door alarms as a fail safe incase anyone gets in... hell turn on the metal detectors.
It is its own fort.