Sure, here are some travel tips for your visit to Ringkøbing, Skjern, and Tarm in Denmark:

Best Time to Visit:
Denmark is known for its variable weather. The best time to visit, though, is from May to August when temperatures are warmest and days are long. However, if you enjoy winter sports or cozying up indoors, the winter months can be charming, just expect short days and cold weather.

Route and Accessibility:
All three cities are easily accessible by road or train from major Danish cities like Aarhus and Copenhagen. The most convenient way to travel between Ringkøbing, Skjern, and Tarm is by car, but there are also local buses.

Altitude and Acclimatization:
Denmark is a lowland area, so you won't need to worry about high altitudes or acclimatization.

Accommodation and Booking:
There's a range of accommodation to choose from in these areas – from hotels to cozy bed and breakfasts, and campsites for the outdoorsy travelers. Booking in advance is advisable, especially during peak holiday seasons.

Clothing and Essentials:
Weather can be unpredictable, so pack layers and don't forget a rain jacket! If you're planning on exploring the great outdoors, bring comfortable walking shoes.

Health and Safety:
Denmark is generally safe and the healthcare is of high standard. It's important to have the necessary travel insurance to cover unexpected incidents or illnesses.

Local Etiquette and Respect:
Danes are respectful and law-abiding people. While exploring, remember to respect local customs and laws, including traffic rules if cycling or driving, and always respect nature, particularly if you're venturing out into rural areas or parks.