Might there be anywhere on the web where I could set up a map, as your site enables, and THEN also import/look up a kml file and overlay it on the map? ...or could you create that functionality?
I believe
Trails.com will allow you to upload and display kml's. You need to register and all that to get access, though.
The functionality was built into the postholer site long ago, but again, it's about authenticating the kml's as malicious things can be done with the clients browser with bad kml's. I'm not up for dealing with that....at the moment. That's why I don't allow the public to upload kml's or link to them.
Apologies for not being more helpful.
-postholer
