MTB recommended, although CX drops with decent tyre width have been used successfully. Charlie rode a 2018 Curve Titanium crossbar 1x MTB running tubeless.
By contrast, Darren rode an ancient (mid-90’s) Giant alloy anchor-weight crossbar 3x MTB running Schwalbe Marathon Plus knobbies with tubes.
The Curve was nimble and handled the technical stuff very well. The tubeless were a bit of an issue. Multiple punctures on Day 3 were manageable, but as the trip progressed the scab kept tearing away from the tyre, and there is only so much latex fluid a tyre can hold. An inner tube was installed when the fluid level dropped, and while this continued to be an issue with punctures, we were able to continue.
The Giant was solid and worry free - it was just really heavy. Unfortunately a recent upgrade swapped the front ring set to one with slightly more teeth (23 to 28). This was a mistake - smaller/fewer teeth would have been better to handle some of the seriously steep pinches - and there are plenty of those. The Giant was walked up several climbs that the Curve rode easily, but maybe that also had something to do with the younger and lighter rider ;-)
Navigation was a mixed affair. We had a Garmin, iPhones withe various apps, and old-school paper maps (purchased from https://www.bikesa.asn.au/ridingmaps). The Garmin was a backup to Strava which we used to record the ride. The app Maps.me with preload maps worked best for navigation. And then when all else failed the trail signs were always there.
Chain Lube is essential every 100km or so - it’s hot and dry out there, and lube not only protects the chain from snapping, it makes each pedal stroke easier.
Spare tubes, self adhesive patches and old-school cement patches are good to have.
Cable ties come in handy for securing water bottles in standard cages. Adjustable cages worked well.
Panadol - saddle sores suck.
Paw Paw cream - saddle sores suck.
Sunscreen - 50+ applied throughout the day.
Snacks - keep the fuel up especially on days when there are no towns, shops or pubs along the way
Keep cup - go waste-free where you can. handy for mornings when the accom has no breakfast.
Airpresso ... gotta have coffee, and these are light and compact.