Yes, the water taxi stop at Hotel Dona Palace is for private water taxi's only. The Vaporetto and Alilaguna boats would not be able to stop there. The S. Zaccaria Danieli "E" terminal accommodates both the Alilaguna Blue Line and the Vaporetto, Line 2. The are actually 3 terminals at S. Zaccaria and the middle one also has Vaporetto Line 1, 4.1 and 5.1 stops. To get to the train station just take the Vaporetto, Line 1 or 2, and get off at the Ferrovia terminal, it's right in front of the train station.