Sure! Vienna, Linz, and Graz are wonderful Austrian cities that have a mixed charm of history, culture, and nature. Here are some useful travel tips for your journey:

Best Time to Visit:
The best time to visit these cities in Austria is from April to October when the weather is mild and perfect for sightseeing. However, if you are a fan of skiing or other winter sports, the period from December to March would be ideal.

Route and Accessibility:
The Austrian cities are well connected by rail and road. Vienna International Airport is the largest airport in Austria and regular flights are available from most international locations. From Vienna, you can travel to Linz and Graz by train or car.

Altitude and Acclimatization:
Vienna, Linz, and Graz are not at high altitudes. Therefore, acclimatization should not be an issue for most travelers.

Accommodation and Booking:
There's a variety of accommodation options available in these cities, ranging from budget hostels to luxury hotels. Ensure to book your accommodation in advance, particularly during the peak tourism season.

Clothing and Essentials:
It is advisable to pack according to the season. In winter, warm clothing and snow-boots are essential, while in summer light clothing would suffice. Also, carry a good quality umbrella as rain showers are frequent.

Health and Safety:
The cities are generally safe, but like in any other tourist place, stay cautious of your surroundings. Also, it's advisable to have travel insurance.

Local Etiquette and Respect:
Respect local customs and traditions. In Austria, punctuality is highly regarded. Also, Austrians prefer a certain formality when speaking and it's customary to greet with a "Guten Tag" (Good day). While visiting churches, dress modestly and maintain silence.

I hope you have a great trip!