Hi Sara,
It was great to meet you and your dad this morning up at Hotham.
The snow seems to be disappearing a little quicker this year (sample size of one, on the Bogong High Plains
) so by the end of November you should be OK, even on the Main Range. The rivers up in NSW caused me a few issues last year but they had come up from rain so there isn't much you can do about that really, just err on the side of caution.
It'll be pretty dry from Hotham all the way to Rumpff Saddle most likely, as I'm sure you know! The tank west of The Twins is on the crest of the ridge so if you are walking Twins Track and not the exact route of the AAWT then you need to climb twenty metres up onto the crest to find the tank. The tank at Barry Saddle is a little decrepit and has some swimmers in it but it's still pretty welcome. You
should get water at Viking Saddle but as has already been mentioned you might have to drop down a fair way, I went north east of the saddle last year but also found water south west at other times.
I'm guessing that it'll be after Christmas when you hit the Razor Viking area, if the weather is warm when you are going through consider starting at first light, have an extended break in the middle of the day and then walk into the early evening. It's rough and slow through here and the lack of surface water makes it even harder. I did Catherine Saddle to Barry Saddle in around 10 hours but I've walked parts of the AAWT through here a few times before (I had sleet rather than heat) If you are feeling strong your best option might be to walk from Barry Saddle to Camp Creek in a looong day, it would be a very hard day though (Camp Creek should have water at Christmas).
Have you considered a food drop and Water drop at Low Saddle instead of Rumpff? Once you leave Chesters Yard water will probably be hard to come by until the creek on Middle Ridge Road south of Rumpff Saddle, it's around but you'll probably have to search a bit and not be too fussy about quality.
Last year when I went through the top of Mt Shillinglaw was pretty indistinct, no worries for me heading north towards the Jamieson Road but harder for you trying to pick the right spur to drop you down to Black River. If you find yourself dropping below the 1150 metre contour with no signs of the old 4wd track then stop and re assess. Once you find it it's easy to follow all the way down to Black River. If you don't want to go looking for Drummo's cabin on Short Spur Track then you'll have to lug a couple of day's water out of Black River to get you down to the Jordan River. From there on everything will be easy
Good luck with the walk...it'll be awesome.