Absolutely! Here are some travel tips for your trip to Rouen, Amiens, Lille, and Arras in France:

Best Time to Visit:
The ideal time to visit these cities would be from April to October when the temperature is pleasant.

Route and Accessibility:
All these cities are well connected by the French rail network, TGV. You can start your journey from Paris. The route would be Paris->Rouen->Amiens->Lille->Arras and then back to Paris.

Altitude and Acclimatization:
All these cities are at low altitudes so acclimatization wouldn't be a problem.

Accommodation and Booking:
It is advisable to book accommodations in advance for the best prices. You can find a range of hotels, guesthouses, and hostels according to your budget and preference.

Clothing and Essentials:
Pack according to the weather. A light rain jacket is useful as Northern France can be rainy. Always pack comfortable footwear for walking around old town sectors, and don't forget your camera!

Health and Safety:
EU health regulations are very strict so tap water is generally safe to drink. However always have travel insurance, and carry essential medicines.

Local Etiquette and Respect:
French people appreciate it when you attempt to speak a little French. Always greet with "Bonjour" (Hello) and say "Merci" (Thank you). It's also custom to say "Bon Appetit" before you start eating when in company. Dress modestly while visiting churches.