Hello! That sounds like an exciting trip to Morocco. Here are some travel tips for your visit to Tangier, Rabat, Casablanca, and Marrakech:

Best Time to Visit:
The best time to visit these Moroccan cities is in the spring (mid-March to May) when the landscape is green and lush, and in the fall (September to October) when the temperatures are mild and comfortable.

Route and Accessibility:
You can fly into Tangier Ibn Battouta Airport from many European cities. From Tangier, you can travel to Rabat, Casablanca, and Marrakech via train or by road. Morocco has a well-developed public transportation system which is relatively cheap and efficient.

Accommodation and Booking:
There are a variety of accommodations available from budget to luxury hotels. It's recommended to book your hotel in advance, especially in the peak visiting season. Websites like Booking.com, Airbnb, or local travel agencies could be used for bookings.

Clothing and Essentials:
Pack lightweight, breathable clothing for the warm days, but also include some warm clothing for cooler nights. Modest clothing is recommended as Morocco is a predominantly Muslim country. Sunscreen, a hat, comfortable shoes, a reusable water bottle, and a power adapter are essential items.

Health and Safety:
Standard vaccinations, as well as Hepatitis A and Typhoid vaccinations, are recommended. Tap water is not safe for drinking, so drink only bottled or treated water. Public healthcare facilities may provide basic services; however, private hospitals are recommended for more serious health issues.

Local Etiquette and Respect:
Moroccans are warm and hospitable. Dress modestly, respect the local customs and religious practices, especially during the holy month of Ramadan. Tipping is customary in Morocco, usually around 10% of the bill.