Hi there! It's great to hear that you're planning a trip to Strasbourg, Colmar, and Reims. These cities are some of the most charming ones in France. Here are a few tips to help you plan:

Best Time to Visit:
The best time to visit these cities in France is during the spring (April to June) and fall (September to November). The weather during these months is pleasant, and these periods generally see fewer tourists, giving you a chance to explore without too many crowds.

Route and Accessibility:
You can start your journey in Strasbourg. You can reach here by flying into Strasbourg International Airport, or by train from other European cities. From Strasbourg, it's an easy train ride to Colmar. Reims is a bit further away, and can be reached with a direct train from either Colmar or Paris.

Accommodation and Booking:
Accommodation ranges from budget hostels to luxury hotels in all three cities. For best prices and availability, it's recommended to book a few months in advance. Websites like Booking.com and Airbnb are useful for finding and booking accommodation.

Clothing and Essentials:
Pack layers and comfortable shoes as you'll likely be doing a lot of walking. A rain jacket or umbrella would also be handy as rain showers can be unpredictable. Don't forget a power adapter for your electronics as the plug type in France might differ from your home country.

Health and Safety:
France is generally safe for travelers. Still, as with any travel, ensure to have travel insurance. Keep emergency numbers handy and always be aware of your belongings, especially in crowded spaces to prevent pickpocketing.

Local Etiquette and Respect:
French people appreciate it if you start any conversation with a polite 'Bonjour' (Hello). Tipping is appreciated but not compulsory in France. At cultural and religious sites, dress appropriately and respect any posted signages.