What an amazing space! It's strange that nobody's moved in. I mean, why not fix up a small corner of it and then take your time fixing the rest?

A friend of mine used to squat in foreclosed homes with her buddies. They'd check the foreclosure notices for potential places, show up with a pickup truck full of tools, and fix up the place for a couple of days - the neighbors always assumed they were supposed to be there. Then they'd live there for a month or a year until the banks came along and kicked them out. But they always left them in much better shape than when they moved in.