Most people can barely manage walking at 2-3 miles per hour on pavement. In the woods, over rugged and likely hilly terrain, in snow, he would probably have been lucky to make 1 mile per hour. And keep in mind that he'd been out there for something like 6 or 7 days already, so he was already likely to be short on sleep, short on hydration, and short on nutrition. On a road or clear trail, rested, fed, and hydrated, 2-3 mph would have been more likely, but it doesn't sound like he stayed on the road for too long.
You are correct.
At this point, few could do much.
I was thinking that many could walk 2 to 3 miles per hour on the dirt road earlier on their disaster. He might have been able to follow his own tire tracks on the somewhat level road.
I am also trying to plant the seed for any lurkers on what to consider if they have a similar event.
Also, I was asking any local FReeper if the closest town was 15 miles away or much more. Apparently there was a cell phone tower remotely available somewhat. If so, he might have been lucky to get a signal.
Going uphill after waiting 9 days in the car short on food and water would be tough.
For any lurker, please consider staying on the road and avoid the temptation of taking a short cut...unless you are a skilled mountaineer. Even many mountaineers die in the back woods.