I have no doubt this would be a fascinating book about an exceptional man.

I would quibble with your assertion that he hiked the length of California "long before the PCT was even a concept". The earliest proposals for a long distance trail from the Mexican to Canadian border date back as far as 1926, while Colin's epic hike was several decades later. This doesn't detract from his accomplishments. The PCT still did not exist as a continuous trail when Colin hiked his Thousand Mile Summer, and he chose a demanding route of his own devising.