Nuts - I've done that ride. It's a solid 60k's of montane - subalpine riding south from Dead Horse Gap to the Pinch River, and travels between 1340 asl at DHG up to around 1580asl then to 1200 asl above the Pinch River (at the top of the 9 Mile Pinch Fire Trail). The great thing there is that it drops from 1200 to 200 asl over about 9 k's, from the range to the confluence of the Pinch and Snowy Rivers.
It's wild and remote country - when I did it with mates we were all riding lots, mainly enduro and long XC both events and recreationally, and it was 5 hours ride time over an 8 hour day for us. Easy for a group to get slowed, lost and demoralised on. We had one set of busted ribs and I still wear the scars and nutted shoulder from a good off. This route also taught me a good lesson in anticipating the experience of others - I sent a mate and his gf down there as a recommendation. They really weren't prepared for long XC MTB and ended up having the coppers searching for them when they didn't make their return time and place. Mechanicals saw them walking down the Pinch in the dark, which would have been very average.
An escorted group like scouts or DoE has a different set of care and responsibilities than a rec group of like-minded mates - I think they did the right thing in pulling the button. But the wrong thing in terms of gear preparation - on a ride like that a spare set of thermals and a rain jacket go in the bag, no questions. It's a long way from anywhere if you gotta walk out.
That said, if you can convince someone to shuttle you back to Jindy / DHG, and have some good XC under your belt, it is my favourite one-dayer MTB ride, ever. Really good.