You captured my interest with just this little bit.  Depending on how the rest is written, I could easily be enticed to return on a weekly basis to hear another episode.  You have a huge array of stories that could be told within this theme, so a series would be wonderful.  CD's could be numerous for a serial story.

As far as timing goes, your story needs to fit within a time frame of a radio program.  First, listen to some, with and without commercials.  See how much time they have available for the actual story.  Then, do as mammajo recommends.  Doing a read through, in the way actors would act the script, with pauses, emotions, words, etc., plus sound effects, and music, would allow you to see how much of what you have written will fit the format of the radio show.

You may find that you have to have different versions written to fit within different time formats.

I used to listen to very old radio dramas while I worked.  I loved the stories, though most were quite overdramatized, which was the custom of the time.   I believe they were from the 40's and 50's.  Well worth listening to in order to get a sense of timing.  I haven't even tried to see if there are any more current radio dramas going on.  Audio dramas on CD's could easily take the place of the radio drama.  I have no idea of the costs involved in producing such works.

I wish you the best in your efforts to get this published.  You have a good idea.

“Music is harmony, harmony is perfection, perfection is our dream, and our dream is heaven”
Henri Frederic Amiel