Sarah, no waist pockets? That is a shame, I found them invaluable for storing my snacks. It's not the end of the world though. Whilst I use water bottles I also use one of the converta tubes for easy access. It's easy to keep track of my water because I have the tube attached to a 500 ml bottle, and top it up when I run out. I know that if I haven't drunk half a litre in 2-3 hours I am not drinking enough. ( More when hot!) Because the water is in my pack it also keeps it cooler. ( Currently it's stopping it from freezing!).
View attachment 162312 One shoulder strap has my GoPro on it, the other has the tube.
I also have a carabiner but it's not really necessary - very seldom used.
Side pockets - one has my poncho tucked in for quick and easy access. I can just reach back, pull it out, and put it on in less than a minute, without stopping. On the other side I often tightly strap-on whatever extra layer I was wearing first thing in the morning. The main reason for that is that I often use it during breaks to ensure I don't cool down too quickly.
The rear mesh pocket has my toilet kit and a spare rubbish bag. At least three safety pins pinned into the back of the bag too ( I carry 10) - I change my socks after around three to four hours and dry them. Sometimes my face cloth. Or of course any washing that hasn't dried from the day before.
Top pockets - outer has lunch, fruit, mini daypack (20l) and a square of bubble wrap for sitting on.
Inner - first aid kit for quick and easy access. A couple of small personal items.
Waist belt I'm wearing is a hangover from former times. Way too big! Pen, small change purse inc. my debit card, phone, power bank, passport and credential ( in a zip lock bag). Notes € in back zipped pocket. I carry absolute Max €50.
(Rest, credit card, 2nd ID is elsewhere, ).
Suggestion would be packed things where you think you would like them. You're about to do your shake down on the Milford track as I recall so you'll soon find out if you've got it right or not!