Please heed the warning signs to only have One person on the swing bridge at a time. A few years ago some people abused these warning signs and resulted in a big group of them being killed when a platform collapsed from excessive overloading.
Besides, it's far more enjoyable and manageable to cross a swingbridge alone, you can get into your own rhythm or even stop half way to take photos as I did.
Never enter the hills or bush in New Zealand without a jacket. We are not a tropical country and it's likely the weather can change without notice and turn very cold. Sometimes the winds and rain seem to come directly from Antarctica and can turn a lovely hot day into a very cold and chilly miserable one.
A good water and windproof jacket is required at all times. Of course if you get lucky you won't use it , but at least you had it in the event of the need arising.