Abandoned buildings in central Florida?

Trying this again....

I'm looking for abandoned buildings in Marion County and surrounding areas so serve as suitably run-down sets for an upcoming movie production. We'll be shooting in the "killer's lair" and we also need plenty of hallways and separate rooms for a few kill scenes. Ideally, it would be an old school, hospital, or large warehouse/factory.

This is an actual movie (third in a series), not some film student project, so the location will need to be accessible legally. If you or anyone you know is aware of such a place, please contact me here on SLS.

Thanks in advance!