Preparation
Logistics
For Walgett to Brewarrina, I launched onto the Barwon River near Barwon Inn (where I stayed overnight). Barwon Inn is several kilometres outside of Walgett near Dangar Bridge. This is about 11 km downstream of the weir at the the Namoi/Barwon confluence. I was able to leave my car at the Inn whilst I paddled down to Brewarrina. On arrival at Brewarrina I stayed at Beds on Barwon which is located just out of town and about 5 km upstream of Brewarrina Weir. The plan was to catch the bus back to Walgett to retrieve my car but this involves a 660 km trip via Dubbo and three separate buses taking a full day. Fortunately, on arrival in Brewarrina a kind local offered to drive me the 130 km to Walgett via the direct route.
For Mungindi to Walgett, I teamed up with Bill of River Kings fame. We did a car shuffle between Barwon Inn and Mungindi. There does not seem to be any public transport servicing Mungindi.
Drinking Water
I was prepared to treat the river water by the process described for my journey down the Darling. I started out from Walgett with close to 30 litres of drinking water and I only treated 6 litres of river water over the seven days. Care must be taken in case of blue-green algae outbreaks that you do not drink any river water even if it is treated. For the Mungindi to Walgett trip I purchased a 4.0 litre Platypus Water Filter which I was very happy with.
Food
I expected the journey from Walgett to Brewarrina to take 8 days for the 290 km and I carried an additional 4 day emergency supply. I expected the journey from Mungindi to Walgett to also take 8 days for the 305 km and I carried an additional 4 day emergency supply.
Maps
I used the topographic maps obtained from NSW SIX Maps. I downloaded fragments of the etopo maps (see second dot point below), printed them, wrote notes on the maps (e.g. distances, information from earlier paddlers and expected Telstra mobile phone coverage) and highlighted sections such as the location of weirs. Then I finally laminated them for use on the deck of my kayak. You may be able to access copies of the maps here: Barwon River Maps.
The distance measurements on the maps done made using a piece of string. Generally I estimate that the accuracy is +/- 3% however, it was less accurate in the twisty parts of the river near Mungindi. The Footpath app, which I have only just become aware of, appears to give accurate measurements more easily than a piece of string.
NSW SIX Maps Here you can view and print NSW topographic and Satellite images of the whole state. There are various tools such as distance measurement.
or
NSW SIX Maps etopo You can download for free a PDF of the relevant topographic map and then in Adobe (free version) you can use the "Snapshot" tool (go to Edit -> Take a Snapshot) to select the part of the map you want. Then you can right click in the selected area to print that part of the map. This provides you with the official topographic map which includes 1 km grid lines. However, it can be annoying when the river crosses the border of the map multiple times!
GPS
I also used Back Country Navigator (BCN) on my Android phone. This app allowed me to download the default maps for offline use on my phone. However, I rarely used it on the lower Murray because the maps listed above were sufficient.
Gear and Safety (including Communications, First Aid and Kayak)
See the information described for my journey down the Darling.
Links
The most comprehensive site for paddling the Murray River and the other major rivers of the basin is Alan Davison's site.