A half-dozen routes to Casablanca alone. As a rule the ones that offer the least direct access to the big cities offer the best bicycling. The area is famous for its hashish production, presents a tremendous problem for the hapless cyclist. They can be harassed by a constant barrage of hashish sellers. The police are suspicious of foreigners and can add to the cyclist's dilemma.
Drugs breed other crimes.
However beautiful, the area is not recommended for cycling. You have to cross to get to or from the inland desert region, but if you are up to the task it opens up the options of some very diverse and exciting loops. The eastern desert has few roads, but for those who want to work hard enough there are get rewards. The sparse population in the area has not seen as many tourist so they offer a more natural hospitality. The route from Midelt to Marrakech offers many scenic sections, and those which are not overtly scenic are nicely spiritual.