Interesting data set, but what I'd want to know is what is the farthest you can get from the farthest road.
This tells us that wherever we are, IFF we walk in one of the 2-3 the optimal headings for that circle, we'll hit a road in ~18 miles max. That's the best worst-case.
What about the worst worst case -- if we head in the most un-optimal direction? How effed are we in that circumstance?
Might not be the worst case and I may have missed a small logging road but if you were to head roughly south parallel to the John Muir Trail from around Tuolumne meadows it would be about 130-140 miles before you reach a road or US-395 around the Kennedy Meadows store. I think you can just miss the roads around Mammoth and Devil's postpile and then the Road's end trail head in SEKI.
Assume you are between any two civilization services and you simply walk parallel to both indefinitely... Seems that's about as bad as it can get. So I guess finding for the longest straight line anyone can take wuthout hitting anything that could rescue you is the answer to your question.
I just watched exactly that last weekend. Not even all that remote (Maroon Bells-Snowmass Wilderness). Guy came down with appendicitis overnight, a 10mi hike in from the nearest road/trailhead.
He was fortunate enough to be able to get out to a major trail and someone with a PLB passed by and called it in, so they could get a helicopter out to him.
But had he been on a slightly less popular trail, he might not have had that luck, and it could easily have been 10 hours for someone to come across him and then speed hike out to a cell signal.
This tells us that wherever we are, IFF we walk in one of the 2-3 the optimal headings for that circle, we'll hit a road in ~18 miles max. That's the best worst-case.
What about the worst worst case -- if we head in the most un-optimal direction? How effed are we in that circumstance?