That time of year it shouldn't be too bad. That's going on Autumn for us. We had snow in the high country in Late april/early may this year. Out there it could be anything from still high 30's to bitterly cold (or at least my version of it). Especially at night!
I'm pretty sure that race has changed significantly in nature I think from when it was first advertised. I seem to remember the entry fee being much higher too! I can only think their attempts to string it together as a "proper" race has failed which has left it in the state that it is.
I'd personally find the lack of defined route frustrating from a competition point of view. I'm not sure the route they are suggesting is particularly interesting. I find it interesting that the entry fees and prizes are listed in GBP and not AUD
perhaps an indication of the market segment they're going after?
A few of us have known about it, but I haven't heared anyone buzzing to do it from this part of the world at least.
There's a few underground multi day Self Suported races popping up though, and a couple people actively trying to plot reasonable routes. There are a couple people riding the bicentennial trail end to end (5000+ km's) in a fastish touring pace. I'm wondering if someone will try and set a reasonable bench mark one day but the trail is not especially mtb friendly
If you want to come to Oz to do a multi day fast tour or "race", I'm sure we could string up some better options for you. Not that I don't think that race won't go through some spectacular country but well... probably not the best Aus has to offer...