Absolutely! Graz, Linz, and Klagenfurt are wonderful cities to visit in Austria. Here are some travel tips for your journey:

Best Time to Visit:
Depending on your preference, summer (June-August) is delightful for outdoor activities while winter offers magical Christmas markets and skiing opportunities. The shoulder seasons (spring & fall) are less crowded and more budget-friendly.

Route and Accessibility:
The cities are well-connected by train, bus, and road network. Linz and Graz both have international airports. Klagenfurt is smaller, but reachable from both cities by train in about 2-3 hours.

Altitude and Acclimatization:
Altitude is not an issue in these cities as they are not situated at a high altitude. However, if you plan on visiting the mountains, take slow walks to acclimatize.

Accommodation and Booking:
Austrian cities have a range of accommodations to suit every budget, from quality hostels to luxury hotels. Booking in advance would be recommended, especially during peak seasons (summer and Christmas).

Clothing and Essentials:
Pack according to the season. Warm clothing for winters, comfortable wear for the summer scoring on comfier shoes for sightseeing. Rain gear is handy as Austria gets rainy spells throughout the year.

Health and Safety:
The cities are generally safe to travel. However, it's always advised to take basic precautions like keeping your belongings safe. In case of emergencies, dial 112. Health insurance coverage is recommended.

Local Etiquette and Respect:
Austrians place a high value on manners and politeness. Greet people with a handshake and always say please ('bitte') and thank you ('danke'). It's polite to say 'Guten Tag' (Good Day) when entering shops and restaurants. Most importantly, respect local traditions and customs.