Marrakech and Erg Chebbi are far enough apart that a quick “desert from Marrakech” label can hide two punishing road days. This route instead uses an Ouarzazate night, with Ait-Ben-Haddou as a meaningful stop after the mountain pass, then protects two Merzouga nights. One can be a camp if its facilities and transfer are genuinely worth it. The full day between those nights leaves space for a dawn dune walk and a village outing; Rissani's main souk is another option if that day falls on Tuesday, Thursday or Sunday. This trip ends in Merzouga, rather than returning to Marrakech. A traveller who must fly out of Marrakech on day five should choose a longer trip or another destination. In winter the pass and cold desert night are the constraints; in summer the heat changes how much time can safely be spent outdoors.