Milford track availability is very low. Huts are booked a year in advance. Luckily, sometimes there are cancelations. In order make sure you see them, you can constantly check the DOC website or use NZtracker service that will notify you once someone cancels so that you can immediately book.
Be prepared to get wet - the weather in Fiorland is crazy and changes rapidly. Don’t forget to take enough extra clothes and spare dry socks. Take a waterproof cover for your bag, your phone and your camera. Make sure you have good hiking waterproof boots. In addition, take a swimming suit. There are nice spots to swim.
Mosquito spray is a must! There are too many sandflies that want to taste every exposed spot of your body. If you react badly to bites and swell up (like I do), it’s better to be prepared in advance.
Food - you can’t purchase any food on the track and have to take food for the whole period with you. It’s better to take lightweight, high energy value and fast cooking food. For example: Breakfast: sandwich, porridge, cereals. Lunch: sandwich, cracker biscuits, snacks, fruits, dried fruits. Dinner: pasta, rice, instant soup or meal. You will need a bottle of 1.5-2 liters of water, tea/coffee and snacks.
Book in advance a hostel/hotel for the night after you finish the track. After 4 days of walking you will be tired and won’t want to start looking for a place to sleep. Arrange your place for 4th night, before you go to the track.
The first day of the track is an easy day of one hour. Therefore, you don’t need to rush. You can easily start the day in the late afternoon and but if you have started early, just relax and enjoy the scenery.
On the last day, it is better to book the late boat trip (usually at 3-4pm). Thus, you won’t have to rush on your last day and will be able to enjoy the beautiful scenery. Trust me, you don’t want to run all the way and miss this wonderful views.