I live close to an east-west part of the 1858 Butterfield Overland Stage route which eventually became US Highway 82. Only 1.5 miles north of me is the Red River (divides Texas from Oklahoma) running (serpentinely) west to east. The original Butterfield route stays in touch with headwaters of creeks running southward into the Trinity River basin (the Trinity runs through DFW) staying just inside the northern edge of the Trinity river basin, or staying just south of the breaks that drain into the Red River. It never strays into watershed of the Red River. Water off my roof flows to the Trinity, a neighbor just north of me drains to the Red River. My guess is beginning with the native Americans they traveled along the Red River for hunting but next to Trinity tributaries for drinking (Red River water is too salty to drink).

And, yes, I am going to do the 100th Meridian in 100 mile samples (good suggestion). I have too much going on to do the ride I’d like. I am going to take notes and put them on Medium as a way of recording at least for myself.