It strikes me as similar to a car rally. A number of testing special stages, separated by reasonably fast transit sections.
It pretty much covers every type of upland terrain in Northern England, crossing three National Parks and three Areas of Outstanding Natural Beauty. It wouldn't take much of a diversion to take in the Northumberland National Park, including Hadrian's Wall. You could take in the Arnside-Silverdale Area of Outstanding Natural Beauty by riding through Yealand Conyers and Warton.