I have re-posted my reply from you "itinerary" thread:
Basically, I think you are trying to do two trips in one. Either do France, Munich and Fussen or Vienna, Prague and Budapest. You almost had me kinda feelin' your itinerary until you dropped the night train bomb - not a good idea as you will be constantly exhausted.
If you do choose to come to Vienna, my first comment is that you are on palace overload. And where does the Hoher Markt come from because it is kind of random - it is just a square you can see in about 5 minutes.
So a Fussen to Vienna trip will take about 7 hours on the train. So I assume that you will arrive late in Vienna, spend the night and then have a day and then leave the next day for the next destination.
With one full day in Vienna, I would suggest that you walk around the first district in the morning, taking in St. Stephan's, the Graben, a coffee shop (Demel's or Central would be my suggestions), walk through (but not in) the Hofburg, see the Rathaus and the Opera from the outside. Take the U4 to Schonbrunn and visit the palace. Have dinner at the Naschmarkt on your way back. I think this is all you have time for.
If you did have more time, I would add the Belvedere and Karlskirche (St. Charles) as they are close together. Vienna really deserves 3 full days, so if you do adjust your schedule I am happy to provide more highlights.
For hotel suggestions, it very much depends on your budget. I like to use booking.com for my hotel bookings and read the reviews on trip advisor. Try to stay as close to the center as you can.
