https://parks.des.qld.gov.au/parks/carnarvon-great-walk/

86k loop of remote technical single track in central Queensland, Australia. 

https://www.summitpost.org/celo-knob/154302

"Celo (pronounced SEE-low) Knob is one of the most remote of our Southern sixers. No matter how you get to the summit, you must either make a climb in excess of 3,000 feet, and/or a long and arduous trek along miles of the most rugged trails in the East."

This is a Premier Route. To claim an FKT on this route, you must meet a high standard of documentation and verification. See details here: https://fastestknowntime.com/premier-routes.

Via Alpina -  Original Red Trail is a 2650K trail that goes through all Alpines countries.
The trace is fully specified and detailed on the official website of the trail: