Sure! Visiting Fes, Meknes, and Chefchaouen in Morocco are experiences of a lifetime.

Best Time to Visit:
The best time to visit these cities is between April and June, and between September and November. The weather is moderate and pleasant during these months.

Route and Accessibility:
There are well-maintained road networks making it easy to travel between these cities.
The train in Morocco is efficient but there are no rail connections to Chefchaouen, you may have to use the bus or a grand taxi.

Altitude and Acclimatization:
The cities are at a relatively low altitude, so there is no significant acclimatization period needed. However, always stay hydrated.

Accommodation and Booking:
There are variety of accommodation options from luxury hotels, Riads (traditional house), and hostels. It's advisable to book in advance, especially if you're visiting during peak seasons.

Clothing and Essentials:
Morocco is a Muslim majority country, so it's respectful to dress conservatively. Pack lightweight, breathable clothing but also include a light scarf or jacket for the cool nights. Don't forget your comfortable walking shoes as you'll be exploring these old cities by foot most of the time.

Health and Safety:
Drink bottled water and watch out for street food hygiene to avoid stomach issues. Consider a travel insurance that covers medical emergencies.

Local Etiquette and Respect:
Respect the local culture and religious beliefs.
Bargaining is common in Morocco, so don't hesitate to negotiate prices in markets. During the month of Ramadan, observe the fasting rules if you can, especially in public places.

Lastly, a phrasebook or a Google Translate app would be handy as English is not widely spoken.