You need to invest in security measures: cameras, 6 outdoor motion lights, better locks, needs new flooring, roof is 30 years old.

Install security cameras or temporary security system.

What camera's are you using?

@Allen Watson I would hire someone to do it or set up some cameras to document the scene.

Helps split costs if things are needed, or clean up, security cameras, etc Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

Does the facility have cameras, a good exterior fence, and electric gates?

I do have a small handheld inspection camera and am ready to drill some small holes in the cavity and look around.Shoot me some ideas!

Put up a camera and a sign that says video surveillance in progress.

I was thinking something along the lines of a Ring system, coded entry knobs, and a few cameras up high on the corners of the building also.  

Your phone has a way of sharing your contact information with anyone quickly and easily using a QR code and their phone camera, or you can send it via text, or email, or messenger, or a hundred different ways.There's a place for business cards but I find them antiquated and unnecessary for most people.