Abandoned homes

Hello all. My fiance and I just took over management of a 220+ space park. The business that owns the park is based in another state. We’ve found there to be 4 vacant homes that have damage from people moving out over the winter and leaving the water pipes on, so these units need the floors and plumbing replaced, along with untold things under the home that we haven’t seen yet. Is there a good method for knowing a place has been abandoned early, other than seeing someone moving out?

We try to keep our eyes peeled, however last month a whole home was pulled out less than 6 hours after we found out it was going to be pulled, which means they packed, disconnected utilities, and prepped it completely under our noses. We patrol the park 4-5 times per day, sometimes more, and at night.

Thank you.