Methods for Researching Abandoned Locations

I thought I would describe my process by which I find all these old places to photograph. Most are well known and well-visited, others are scarcely known. Here's a basic rundown of my process:

Known Abandoned Sites
    If still existing:

•  check information on web
•  check google earth (check date of imagery to confirm standing)
•  check USGS aerials
•  check NETR aerials (may be redundant with USGS)
•  check sanborn fire insurance maps (if in populous place)

Unknown Abandoned Sites

Using proximity of other known locations

•  check USGS aerials (of older date) for buildings of interest in area
•  check google earth to see if still standing

If still standing

•  check information for building on web
•  visit site in person for images and research

If NOT still standing

•  check for remnants, pathways etc (if demolished recently or if in a location untouched)
•  visit site in person to see if any interesting pieces remain