Teri - I can relate to initially being skittish about visiting Morocco, or driving there. It's different in some obvious ways from Europe: it's an Islamic country, you'll hear the call to prayer frequently, it's in Africa and the developing world, it looks and feels (and is) pretty culturally "exotic." We may have conscious or subconscious fears of the whole Arab world (thanks to media depictions and history). The writing (in Arabic script) looks just like incomprehensible squiggles to most of us.
So yes, it is "different" from going to, say, Paris. But it's also surprisingly similar, familiar, and - this will probably come as a shock - is a major magnet for tourism for (mostly) people from western Europe. Mass tourism is a highly visible presence in parts of Morocco, with northern Europeans looking for their hit of "sun and fun", you'll see stag parties, groups of football (soccer) hooligans, low-cost flights from all over the continent, ATMs, fast-food chains, consumerism, and crowds of tourists that look just like you and me. Think "Cancun" rather than Kabul. Kind of. French is spoken widely (and badly, just like my French), so if you can manage even a tiny bit of bad French, that helps a lot with the anxiety and perceived language barrier - you'll see signage in Arabic, French and English. Anyone in the tourism business that you need to deal with will speak French and English (and probably a dozen other languages). You'll also see a LOT of other international tourists.
I've been to Morocco several times. First as a solo backpacker, then as a couple with my spouse. I have never felt in any real danger, although I did get hassled by touts a lot on my first trip (touts are still present, but they don't seem nearly as bad as they once did). I can understand how a solo female might be hesitant (I did meet several American and European women traveling solo on my first trip; they described the hassles they encountered as not much more annoying as those they experienced in places like Italy). As a couple or in a group, I would not let that keep me away.
I found the driving in Morocco easy (in fact, easier than in many places in Europe). In Marrakech itself, yes, you will need your wits about you as driving there is a mix of no-big-deal and utter chaos. If you simply drive away from the rental location to the highway up and over the High Atlas Mountains, it'll just be a few minutes of stressful driving before you get on roads that feel like driving anywhere (same for the return).
From a practical standpoint, it will simplify things a great deal if you have a car for this out-and-back from Marrakech. If you are up to the challenges of renting and driving a car in other foreign lands, I don't think you should be put off doing that in Morocco. Our side-trip over the mountains and out to Ait Benhaddou was great - it's an incredible site. Whatever you decide to do, I think you'll find it very worthwhile. Hope some of this helps.
