In the north and west of Morocco, major roads will be hard surfaced roads but south of the High Atlas mountains, they are less common and travel in the mountains can be difficult in winter. Morocco does not have a good road safety record and care is required, particularly in the dark where you need to ready for unlit obstacles, vehicles or animals

Bus

Traveling by bus is a very economical way to get around Morocco and in most cases they are reported to be very good, with a much larger network than the railway.
There are local bus companies operating in different areas plus national companies such as CTM and Supratours, offering transport between most cites.
Bus from Casabalanca to Marrakech will cost around 10 pounds.

Hire Car

Hire cards are available but not as cheap as you might expect. For comparison, figures quoted by a major international company for a 4/5 door saloon, similar to a Ford Mondeo for one week are as follows:
Gatwick, UK, 211 Pounds
Alicante, Spain, 188 pounds
Casablanca, Morocco, 461 pounds

Fuel prices in Morocco are around 70% of UK prices or 170% of US prices

Petite Taxis

These are small taxis limited to a maximum of 3 passengers and generally found in the cities and have meters. They are quite cheap - if 3 are sharing, they can work cheaper than a bus.

Grande Taxis

These tend to be large Mercedes (not new), catering for upto 6 passengers and can be used for longer journeys. These do not have meters and the price needs to be agreed before the journey (negotiating skills may be required). Unless you or your party are paying for all 6 places in the taxi, the driver may wait for more passengers.