X2

for morocco you should plan on marrakech, tangier, and fez.
casablanca is the largest city and the comemrcial hub but honestly aside from the hassanII mosque there is not much to see.

a day or so in Rabat would be good, more historical stuff and, Meknes is another day thing, teh roman ruins by it are one thing, moulay dris the oldest mosque in teh area is another, moulay ismail tomb is a major monument, old city gates and walls are also nice.

fez/fes is ahistorical city, has a huge sufi festival, but i think u will miss it timing wise.

but really if u have limited time i would say go to marrakech only