A short trip from Glenorchy to Milford Sound at first following the Caples Track along the Caples River and then the Milford Highway along the Hollyford River.  4000 feet is a good altitude but be at 5000 ft at WP18 the Homer Saddle the highest point of the trip.  Beware NZMF is about 6nm from here at Sea Level.  Best to fly over and inspect the Sound and come back to land if it is your first time here.