Sure, I'd be happy to help! Here are some tips for your upcoming trip to Esch-Sur-Alzette, Esch-Sur-Sûre, and Vianden in Luxembourg:

Best Time to Visit:
The best time to visit Luxembourg is usually between May and September when the weather is warm and welcoming, ideal for sightseeing during your visit to these towns.

Route and Accessibility:
The towns of Esch-Sur-Alzette, Esch-Sur-Sûre and Vianden are all accessible by car or public transportation. Luxembourg has an excellent public transportation network, including trains and buses, which can take you from one city to another.

Altitude and Acclimatization:
Luxembourg, including the towns you are visiting, is not very high in altitude. There should not be any acclimatization issues.

Accommodation and Booking:
Each of these towns offers a range of accommodations for tourists, from luxury hotels to affordable guesthouses. It's highly recommended to book your accommodations well in advance, especially if you're traveling during the peak season.

Clothing and Essentials:
The weather in Luxembourg can change quickly. Pack layered clothing to adapt to changes in the weather. Always have a rain jacket or umbrella handy. If you plan on hiking in places like the Our Valley in Vianden bring suitable footwear and a map or GPS.

Health and Safety:
Luxembourg has a high standard of healthcare facilities. However, it is recommended that you bring all necessary medications and maintain travel insurance for your trip.

Local Etiquette and Respect:
Luxembourg's society is multilingual and multicultural. People appreciate it if you make an effort to say a few words in their language, even if it's just 'hello'. When visiting churches or castles, be sure to dress modestly and respect any signs indicating silence.

These are just a few general tips. Along your journey, you are sure to discover the wonderful hospitality, rich history, and stunning landscapes that make Luxembourg a unique and rewarding travel destination. Enjoy your trip!