It's good to get a decent block of riding in heat beforehand, and to get used to how your body feels when it's working well, and when it's stressed. People have died from heat stroke and hyponatremia at the Alpine Classic in the past. Pushing too far can be a once-in-a-lifetime mistake.

http://en.wikipedia.org/wiki/Hyponatremia

As well as keeping your fluid levels up and your salt, you may find that you benefit from water cooling - regular dousing with water. It'll cool you quite effectively. Every chance you get, douse yourself with water. Stop at shops on the way to refill your dousing biddons. Use the creeks beside the road on Buffalo, and the motorbikes. Use them. Douse like Floyd. It works.

Don't go out too hard too early, but don't waste precious 'cool' time having long breaks. I was stunned by how many people stopped for 30 mins+ at Mt Beauty for breakfast or something before they did Falls, all that did was make Tawonga Gap hotter for them later. Eat while riding, use the cool part of the day as much as you can. Roll down the descents, use them for cooling.

I carried 4 biddons, 2 in the frame and 2 in those tri-bike behind the seat carriers - one was an 'ubermix' of staminade, which I used to squirt into one of the frame biddons and I kept the other frame biddon with fresh water only in it. The ubermix was about 10 times the normal concentration and had the consistency of salty grit, but it decanted well into the other biddon and made dilution easy, I didn't have to try and deal with tablets when parched or muck around with powders etc. Refill? Squirt ubermix, fill with water, done .... Water was plentiful en-route and I didn't need a backpack - I preferred to refill regularly from the water support motorbikes and I stopped off at Mt Beauty on the way to Tawonga gap at a servo - if you need to, use servos cold drinks. Carry $50, it doesn't weigh anything but it can get you a few ice creams and cold drinks etc. Just because AUDAX supports the ride doesn't mean you can't stop and supplement.

And the second most important thing - pace yourself, I saw many people flaying themselves on the first climb up Tawonga gap, and then having to rest at Mt Beauty before going up Falls. I would wager that few of them finished. The tortoise will beat the hare at the AAC.

The most important thing - if you feel bad, stop and get help. The AAC can kill. Don't be one of its victims.