Part of Marrakech's genius is that it sits at the centre of everything. The city rewards days of its own, but it is also the launch pad for some of Morocco's most spectacular country, and a longer stay is far richer for a day or two spent out beyond the walls, in the mountains and the desert the city was built to trade with.
The Atlas Mountains are the nearest escape and the easiest. An hour's drive lifts you from the heat of the plain into Berber villages, terraced valleys and the cool air of the foothills; the Ourika Valley and the villages around Imlil, under the great bulk of Mount Toubkal, make for a classic day of walking, mint tea in a village house and a very different Morocco from the medina. Lonely Planet's guide to the wider region is a good place to weigh the options.
The coast is further but glorious. Essaouira, three hours west on the Atlantic, is a fortified, wind-blown, blue-and-white port town of ramparts, seafood and surf — as relaxed as Marrakech is intense, and a favourite overnight escape for anyone who wants a lungful of sea air midway through a trip. Many people who mean to go for the day end up staying two.
And then the desert, the great Moroccan dream. The full Sahara — the dunes of Merzouga or the nearer sands of Zagora — is a two or three-day expedition rather than a day trip, taking in the Atlas passes, the kasbahs of the Draa and Dades valleys, and a night under more stars than you have ever seen. It is a long way, but for many it is the single most memorable thing they do in Morocco.
The trick is not to overreach. Marrakech day trips involve real driving, and cramming three into a week leaves you seeing the inside of a car rather than the country. Pick one mountain day, perhaps one coast overnight, and save the desert for a trip built around it. Space them out, and the city you come back to each evening feels all the sweeter for the distance.