On our website we have several map previews for various KML datasets. When clicking the preview button the link would go to:
http://maps.google.com/maps?q=http://magic.lib.uconn.edu/magic_2/vector/37800/statect_37800_0000_2010_s100_census_1_kml.kmz
which would show a map with the overlaid KML file.
Support for this syntax from Google Maps apparently has stopped working recently, and I cannot find any new information about adding KML layers to a Google Map using the q parameter in a URL. Most of the resources I have found are for JavaScript or embedding maps, which hasn't been helpful. I have also found this thread from StackOverflow (Why has google maps "q" parameter stopped working?) but this is related to a specific location rather than adding a KML file. If anyone has new information or can help, that would be greatly appreciated.