I did a lot of research before we went to Fes. Casablanca has very little appeal to most tourists except to connect on flights.
You can take trains (see seat61.com) and make your way on to Marrakech or Fes. I had no interest in Marrakech but thought Fes was somewhat fascinating. I would not return to Morocco (cultural issues/oggling/grab-ass) I put it down to been there, done that experience but I'm a whole lot older than you (and juts a bit particular--aka b-witchy about some stuff) but it may be exactly what you'd love!!
relatively cheap if you don't get ripped off (oh yeah--didn;t like that prospect and it's rather frequent there)