I'm not sure how well his makeshift snowshoes performed, but the journal of his account during the time he waited for someone to find him portray him as more resourceful than most hikers I've met.
As to his distance from civilization, I'm assuming you refer to Lagunitas Campground to hwy 285. That is around 20 miles as the crow flies, more like 30 miles on trail from what I see on CalTopo, but with thick fresh layer of snow covering the trail, he'd have had to find his own way (assuming he knew hwy 285 was there). Navigation in a snow covered land that is high in elevation yet hilly but flat enough to hide what's coming ahead can make 30 miles be very very challenging even without the mental challenge of coping with being wet and cold every day.
He was also hoping, at least at the beginning, that they'll find him, and that must have been a consideration for staying in the same place rather than risking losing the trail.