Given the distance between these three cities, air travel is recommended for this one-day adventure. Round-trip flights can cost as little as $150 and take around 2-3 hours in total. For those who prefer train travel, the Eurail Pass is a convenient and cost-efficient option.
If you have more time, consider hiring a local guide to enhance your experience at each destination. Alternatively, if you have less time, skip one of the palaces to allow more time to explore the city itself. Either way, grab a copy of "The Unofficial Guide to Disneyland Paris" or "Rick Steves Vienna, Salzburg & Tirol" to make the most of your trip.