My thoughts on this -
- What temp-rates can I expect during days/nights? So cold we’d need a down jacket?If you can justify the weight, certainly stuff them in. Weather is never a set pattern down here and it can do anything.
- Are gaiters really necessary?I would agree yes. I don't do any walks without them.
- Are our -10°C goosedown bags sufficient for that time period?Sounds good enough to me - if you get cold in that you have your spare set of clothes, right? And worst case, your down jacket / vest too.
- Is it advised to carry EPIRB’s? And how many people will there be on the track in that period, enough to avoid carrying the EPIRB?Advised? Yes. Mandatory? No. But given the remotenss you will be in, I would recommend taking one - hiring one is the best option.
- We land in Devonport, does anyone knows a good hostel or a reasonably prices place to sleep?Plenty of time to do some googling for you if this doesn't get answered beforehand.
- Where can we get supplies (food and fuel) before we start the walk (Devonport or nearby)? Any specialized hiking-stores with trekking food in the neighborhood?Has been answered well. Maybe I can dig out a map and show you addresses if you need so ask, ok?
- Can we get our extra luggage (which we won’t need during the walk)to be sent at the endpoint of the trackI am not sure on this, the bus company would be the best one to find out. Surely they cater for this sort of thing as I bet you are not alone in this request.
- Will we have to cross any rivers; what can we expect? Rivers and streams are all bridged - no swimming required. Expect a track that consists of walking over a mixture of boardwalk, rock paths, rooted slippery forest floor mess, ankle-deep mud, rocky terrain, etc. Some steep sections but the trick is to not overdo it, you are there to enjoy it so take your time.
- Feel free to give any advice you would think I might need!!Apart from what you have asked already, I think most of it has been covered pretty well elsewhere with a bit of searching other topics or other resources.
The "horror stories" are along the lines of people doing the walk without a sleeping mat, wearing jeans and no gaiters, taking a stove they've never used before and having someone help fix it halfway along the track to avoid eating cold food, many other stories.
There are some good guidebooks available -
John Chapman writes the
Overland Track book
Frankinoz has a blog where he has put together an
e-bookThe
Parks site has plenty of info
Who knows what else is out there.
Hope that helps.