http://legacy.kcrw.com:81/pl/ seems to be where the playlists are hosted.

if, as a surfer, I go to:

http://legacy.kcrw.com/pl/NowPlayDayNew.html

It gives me a left hand panel where I can select by date a playlist to display. This playlist links to an actual HTML file, for instance for April 1,2008:

http://legacy.kcrw.com:81/pl/080401.html

Obviously, it doesn't want to let WebDumper snag the entire directory, that gives me a 403 Forbidden.

Am I stuck doing these manually, or is there some trick to grabbing these with WebDumper?

This page makes intensive use of Javascript to make impossible for web retrievers like Web Dumper to download files.