Let me add another possibility for your consideration. On the WC last spring we elected to take the optional day long excursion to Rabat. It wasn’t cheap but we were using Viking’s money so that wasn’t much of a concern for us…YMMV.
it was a long day but the 1 hour drive each way wasn’t as awful as I feared. We got a panoramic tour of Casablanca coming and going and because we were back in plenty of time, we got a drive by of Rick’s and a short stop at the Mosque and at a souvenir place that supposedly was all locally made. I didn’t see anything special but I’m not a shopper.
The day in Rabat included a stop and exterior walk at the Palace, visit to the Mausoleum of Mohamad V, a visit to the Oudaya and its view of the beach, delicious and fun tagine lunch and a walk through the casbah before we headed back to Casablanca.