Certainly, exploring Prague, Vienna, and Budapest can be a fascinating journey. Here are some travel tips to ensure a smooth travel experience:

Best Time to Visit:
Ideally, the best time to visit Prague, Vienna, and Budapest is during the spring (April to June) and fall (September to October) when the weather is pleasant without extreme temperatures.

Route and Accessibility:
Prague, Vienna, and Budapest are conveniently linked by an efficient rail network. You could start at any one of the cities and then move onto the next by train.

Altitude and Acclimatization:
You don't need to worry about altitude sickness in these cities as all are located at low altitudes.

Accommodation and Booking:
There's a wide range of accommodations available in all three cities, from budget-friendly hostels to high-end luxury hotels. It is recommended to book your accommodations in advance, especially during peak tourist seasons.

Clothing and Essentials:
Pack according to the season of your visit. Comfortable shoes are necessary due to the amount of walking you will likely do to explore these beautiful cities. Don't forget to pack a waterproof jacket/umbrella as rain is quite frequent.

Health and Safety:
European cities are generally safe, but do watch out for pickpockets in crowded areas and tourist hotspots. Also, consider getting travel insurance for any kind of health and safety emergencies.

Local Etiquette and Respect:
Respect the local culture and traditions. When visiting religious sites, dress modestly, and keep noise to a minimum. Tipping is customary in restaurants, with 10-15% being a common amount. Oh, and learn a few basic phrases in the local languages—it's appreciated!