Jnyusa,
You are correct about the Bree perspective. This is what is known in Bree from LOTR:
But in the wild lands beyond Bree there were mysterious wanderers. The Bree-folk called them Rangers, and knew nothing of their origin. They were taller and darker than the Men of Bree and were believed to have strange powers of sight and hearing, and to understand the languages of beasts and birds. They roamed at will southwards, and eastwards even as far as the Misty Mountains; but they were now few and rarely seen. When they appeared they brought news from afar, and told strange forgotten tales which were eagerly listened to; but the Bree-folk did not make friends of them.
Gandalf adds a little knowledge later about the Dunedain and the North.
The OED has the generic wanderer definition first and the scout association as third. I believe that it may be that rangers, who were those who wandered the land for their own purposes, developed knowledge and skills useful to the military, and were hired as scouts by the military. They were sometimes called rangers and sometimes called scouts. So the civilian aspect seems to be congruent with Tolkien. It is difficult to deny a military connection, though, since Aragorn the Ranger, is in fact King.
I did check with a friend who lives in General Butler's house (1825). The period of the Mexican Wars is connected with Butler's family. She says in the period from 1812 to the 1850s, several groups of rangers existed, including the Texas group, which alone lasted beyond the Mexican War. They were civilians who the military hired because of their special knowledge of an area.
I'm sure this is far more than anyone but me wanted to know.
In case I forgot to say, Ranger is fine with me.