18.7 miles is a long distance. If you're 18.7 miles from the closest motorized access point, you're in the middle of 1098 square miles of untouched land. Based on my memories of exploring the woods as a child, you could spend a full year getting to know the details of even a single square mile of natural landscape.
I think it's an interesting irony here that, primarily because of motor travel, we imagine that an 18.7-mile radius is not that substantial. (Yes, a marathon is more distance than that, but those are usually on paved roads and not through wilderness. The legend is that the first to run a marathon died of exhaustion on its completion.)
A square mile is referred to as a "section" in the parlance of the public land surveying system. That is also 640 acres. (260 hectares for those of you without acres)
I looked at buying 1,000 acres of wooded land in southern Colorado (at the time it was selling for $240/acre or just under .25M$ during the dot com days) It was part of a 60,000 acre sheep ranch that was being broken up. I could easily spending years exploring a parcel that size.
I think it's an interesting irony here that, primarily because of motor travel, we imagine that an 18.7-mile radius is not that substantial. (Yes, a marathon is more distance than that, but those are usually on paved roads and not through wilderness. The legend is that the first to run a marathon died of exhaustion on its completion.)