The road east to Marrakesh goes along the R207 road. Right at the south east corner of the city there is a roundabout where cars can stop easily. At a small distance from there seems to be a popular spot for police patrols, which makes it unlikely that people pick up hitchhikers. Locals recommend the petrol station to the west, which works fairly well.
===North to [[Safi]] ===
If you follow the same route as if going to Marrakesh, there's a second roundabout a few kilometers out (maybe 3km?) where you can catch a ride on the R301 north along the coast.