Absolutely, these cities are vibrant, full of culture and history and a great joy to visit. Here are some guidelines for a wonderful trip to Marrakesh, Fez, and Casablanca:

Best Time to Visit:
The most favourable time to visit Morocco is during springtime from mid-March to May and autumn from September to October. During these months, the weather is comfortable and pleasant.

Route and Accessibility:
Your point of entry will probably be Casablanca, which is easily accessible by air from major international airports. Marrakesh and Fez both have railway and bus connections. You may consider renting a car if you want to visit all three in one trip as they are several hours apart.

Altitude and Acclimatization:
These cities are at low altitude, so you won't need to worry about acclimatization. However, it is always a good idea to stay hydrated, particularly in the heat of summer.

Accommodation and Booking:
There is a variety of accommodations ranging from luxury hotels to budget-friendly hostels. Riads, traditional Moroccan houses turned into bed and breakfasts, offer a unique experience. Booking in advance is recommended especially if you're visiting during peak tourist season.

Clothing and Essentials:
Morocco is a Muslim country. Therefore, out of respect, try to dress modestly. Women might choose to wear a headscarf, especially in Fez. Loose, breathable fabrics are recommended due to the high temperatures, particularly in Marrakesh. Don't forget a hat, sunglasses and sunscreen!

Health and Safety:
Take care with street food, it's delicious but might not always agree with Western stomachs. Stick to bottled water. Do be careful of the traffic; it can be a bit chaotic.

Local Etiquette and Respect:
Moroccans are friendly and hospitable. Always ask before taking people's photos. Marrakesh is known for its markets. Fez, being the oldest city, is rich in history and culture. Respectful behaviour and courtesy go a long way. Try to learn a few basic Arabic or French phrases; your efforts will be appreciated.
In Casablanca, don’t forget to visit the famous Hassan II Mosque, it's one of the few open to non-Muslims.