Is Nueschwanstein Castle still on this tour? It seems to have disappeared from the Itinerary (replaced by a brewery)?
There was an extensive thread on this maybe a month ago?? Try to search for it. I believe the answer was no, the castle is no longer on the tour. My suggestion at the time was if the castle is of interest, arrive or stay a few days longer. It is very easy to visit on your own from Munich. If you choose to do this, I would suggest visiting Hohenschwangau first as they provide some background and context for the Nueschwanstein tour and Hohenschwagau is decorated and was actually lived in.
It's difficult to know exactly which tour you're asking about but if it's Best of Munich, Salzburg and Vienna, this thread might informative.
LOL, as you'll see, there are fans of the thing, and just as many in favor of giving it a miss. If intent upon doing this as a day trip on your own before or during your RS tour, this might be helpful: