Sure, it would be a pleasure to give you some insight into your upcoming travel to Rabat, Meknes, and Fez.

Best Time to Visit:
The best time to explore these cities in Morocco is in spring (April and May) or fall (September to November) when weather is mild and pleasant.

Route and Accessibility:
These cities are well connected by railways and roadways in Morocco. Rabat, the capital is easily accessible through flights. From Rabat, you can travel to Meknes and Fez by train or bus.

Altitude and Acclimatization:
These cities are not situated at high altitudes so acclimatization is not generally a concern. However, hydrating yourself always helps.

Accommodation and Booking:
All the three cities offer a range of accommodations from luxury hotels to budget hostels. It is wise to book your accommodations in advance, particularly around local events and festivals.

Clothing and Essentials:
In terms of clothing, modesty is appreciated considering Morocco is a Muslim country. Shoulders and knees should be covered especially in religious places. Sturdy and comfortable shoes are advisable as there can be a lot of walking in these historic cities.

Health and Safety:
Ensure to have travel insurance. Contaminated food and water can be an issue, so always prefer bottled water and well-cooked food. It is wise to carry a basic medical kit for emergencies.

Local Etiquette and Respect:
Respect the local traditions and customs. During the holy month of Ramadan, eating, drinking or smoking in public is considered disrespectful. Arabic is widely spoken, but people understand French too.

Enjoy your trip and make the most of Moroccan hospitality!