I've attempted a ride 2x now, the 'Tour of Idaho', have not made it but not for lack of trying. Its ~2300 miles, 10 days to finish, all REMOTE hard (black diamond) singletrack in gnarly backcountry Idaho, several 10k foot peaks, lots of water crossings, sand dunes, rock gardens, bushwhacking trails, list goes on. It's set up kind of like a rally where you have set routes during a day, start and finish, no outside help and you can pick 1/2/3 person team. More people there are the harder the route gets. At the end of it all you submit GPS file for approval and "finisher" status. Days are anywhere between 270 - 180ish miles, D1 for instance is 250 miles and takes good riders 15 hours to complete.
Days typically start at 4-5am and end anywhere from 5 pm to 1 am.....
There are several sections that if you dump your bike off a sidehill, get hurt, get lost or have a bike problem....it's a 15+ mile hike to a gravel road that may see a car every 2 weeks and another 15 miles to a road that is who knows how far from a town of 500 people.
Bikes are pretty unique, need gear for incliment weather, bivvy, full suite of tools, SHOES (if you need to walk out), 200+ miles of range and one person on the team must have a chainsaw, 340 lbs all gassed up and is a nightmare to wrestle around singletrack:
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