I find adrenaline makes me hypo.
And yeah, it's a really long walk so you need to bear that in mind.
I've only been with a group once, usually just the two of us, so no designated bag holders. I've found it helpful to pack kit into little tins and wear combat trousers with buttons on the pickets so I don't lose stuff on rides. And take glucogel or some glucose tablets. You'll spend for ever in queues if you go in July so you must take hypo treatments as it's too long a walk if you're going hypo.
I usually cheat by going in may. No queues and get to go on nemesis loads of times!
Also if it's sunny you're going to want to put sun cream on!