Hello! That sounds like an exciting trip to Austria. Here are some travel tips for your adventure:

Best Time to Visit:
The best time to visit Salzburg, Innsbruck, and Zell Am See greatly depends on what you want to do. For sightseeing, the months from May to September offer pleasant weather. For skiing, the best time to visit is during winter months, from December to March. The shoulder seasons of spring and autumn also offer beautiful scenery with fewer tourists.

Route and Accessibility:
The most convenient way to travel to these cities in Austria is by train which is known for its efficiency and punctuality. Salzburg is well connected to Vienna and Munich. From Salzburg, Innsbruck is a direct train ride away. Similarly, Zell Am See can be reached from both Salzburg and Innsbruck.

Accommodation and Booking:
These cities offer a variety of accommodations, ranging from luxury hotels to budget-friendly options. Booking in advance, especially during the tourist and ski seasons, is highly advised. Websites like Booking.com or Airbnb provide ample choices, photos, and customer reviews.

Clothing and Essentials:
In general, it's a good idea to pack layers, as weather in the Alps can be unpredictable. In the winter months, warm clothing, snow boots, and thermal layers are a must, while in the summer, lightweight clothing with a few warmer options for the evenings would suffice. And don't forget your skiing gear if you plan to ski.

Health and Safety:
Austria is generally safe, but it's always a good idea to have travel insurance. Besides, when doing outdoor activities, stay mindful of weather changes. If skiing, always observe safety measures, wear proper gear, and do not venture off marked slopes.

Local Etiquette and Respect:
Austrians value manners and politeness. A simple greeting in German like 'Guten Tag' (Good day) is always appreciated. Remember to respect the local environment, especially when enjoying outdoor activities in this picturesque region.