My family of 7 is planning a day trip to Vienna from Budapest on Dec 30. Would it be better/easier to take the train or a private transfer? My understanding is that a private transfer would be faster and cheaper for the 7 of us. If a private transfer is the better method, will it be safe during this time or will icy roads be an issue? I am not familiar at all with the roads from Budapest to Vienna. Any other suggestions/tips would be greatly appreciated!