The Grand Staircase Loop is a four-day (ymmv) bikepacking route through Grand Staircase-Escalante National Monument and the Glen Canyon National Recreation Area. It is remote. Most of it is totally inaccessible by car, so there will be few people there to aid you should you need it. It is the desert, after all.
Here, take it from Bikepacking.com
Difficulty: The route travels almost entirely on dirt roads and is 98% ridable with generally intermediate and sustained climbs, containing just a few steep spots that might necessitate a push. Some stretches can be a bit sandy, so plus size tires are preferred but not necessary. Be forewarned that sections of the road are composed of gray bentonite clay which is IMPASSABLE when wet. In rainy conditions it will stick and cling to anything it comes in contact with, forming giant clumps of concrete like mud that gather on your shoes, tires and drivetrain. Riding a bike becomes impossible and even walking can prove extremely difficult. In the warmer months this route can be extremely hot and very committing with long distances between unpredictable water sources. For that, it is certainly not a beginner route and we’ve upgraded it to a 6/10.
The guy in this video, Darwin, runs a popular Youtube channel discussing all things long-distance backpacking. He’s recently taken up adventure cycling, and here he discusses the intense challenge of this route.