There are many beautiful drives in NZ, but there is no doubt the best is the drive from Te Anau to Milford Sound, via the Milford Road and Homer Tunnel. But be warned – pick a time to avoid the buses if you are in high season.
Too many people rush this trip as it is a long day to get to Te Anau and back, after allowing for time in the Sound. Instead, take your time and figure out where to stop for a night or two. Do a few hours on the Routeburn or some of the other short walks around the Hollyford Valley, or stay in Milford or on one of the overnight boats.
In any event, the best way to see Milford Sound is on a boat. Then it is all about the waterfalls, the mountains that appear to leap out of the sound and the wildlife, including seals and dolphins.
Best time to do this? Fine weather immediately after a big storm when the waterfalls are going crazy!