Hello! It's great to hear that you are planning to visit Austria, covering Vienna, Salzburg, and Innsbruck. Here are some travel tips for your journey.

Best Time to Visit:
The best time to visit Austria greatly depends on your preferred activities. If you’re looking to enjoy Austria's cultural history, museums, and urban scene, the months between April to October should be ideal when the weather is typically warm and accommodating. For winter sports especially skiing, the months of December to March are perfect for a visit to Salzburg and Innsbruck.

Route and Accessibility:
The best route to cover these cities would be to enter Austria via Vienna, proceed to Salzburg and end at Innsbruck. Vienna's international airport (Vienna-Schwechat) is well connected worldwide. Once you're in Vienna, the easiest and most convenient way to travel between these cities is likely by train. ÖBB is Austria's leading railway company, and they offer frequent connections between these cities.

Accommodation and Booking:
Best to book your stay prior to your visit, accommodations ranging from luxury to budget options are available in all these cities. Bookings can be done via popular travel portals like Booking.com or Airbnb. It's also recommended to stay within the city centre for easy access to major tourist attractions.

Clothing and Essentials:
Pack according to the season of your visit. For summers bring lightweight, comfortable clothing with a good pair of walking shoes, sunglasses, and a hat. Winters require heavier clothing, including coats, gloves, and scarves. Don't forget to pack a universal power adapter, Austria uses Type F sockets.

Health and Safety:
Austria is a safe country for tourists, however, basic precautions like keeping your belongings safe are always advised. If you're planning on winter sports, make sure you have proper equipment and training. No specific vaccination is needed for Austria, although you should be up-to-date on routine vaccines such as measles-mumps-rubella (MMR) vaccine, diphtheria-tetanus-pertussis vaccine, varicella (chickenpox) vaccine, polio vaccine, and your yearly flu shot.

Local Etiquette and Respect:
Austrians generally appreciate politeness and formality. When meeting someone always use formal modes of address using ‘Herr’ (Mr) and ‘Frau’ (Mrs) with the surname. It's also customary to say 'Guten Tag' (Good Day) or 'Grüß Gott' (God's Greeting) when entering shops or restaurants.