I don't have much to add except a suggestion to do Milford first thing in the morning or late evening, I booked cruise to start at 4.15 pm I think, and I can confidently say that it was hands down the best experience of my life, Milford Sound truly is 8th wonder of the world. I did late evening because we wanted to stop in Te Anau for lunch and a few other spots along the way.
Drive from Queenstown to Milford is quite scenic too although not as scenic as the drive to Blue Pools/Haast,