So, as far as we can tell, the earliest printed version of the song is in Carl Sandburg's American Songbag (1927), page 462.

Here are Sandburg's notes:

A hoss wrangler brought a car of ponies to Duluth, Minnesota. The next day, after brave stunt riding, he was laid in a hospital bed with "ruptures on both sides." He told the surgeon, Dr. T.L. Chapman, in a soft, forgiving voice, "That was a terribly bad hoss - not only throwed me, but he trompled me." Out of past years this rider had, Dr. Chapman's examination disclosed, "bones of both upper and lower legs broken, fractures of collar bone on both sides, numerous fractures of both arms and wrists, and many scars from lacerations and tramplings, the bones knit any way that God and Nature let them heal." As his strength came back he sang across the hospital ward in a mellowed tenor voice. And they always called for more. One song was "The Colorado Trail," remembered by Dr. Chapman as here set down.

So, these are the earliest known printed lyrics for this song.

COLORADO TRAIL

Eyes like the morning star
Cheek like a rose;
Laura was a pretty girl,
God Almighty knows.

CHORUS
Weep all ye little rains,
Wail, winds, wail,
All along, along, along
The Colorado trail.

---

In the initial post, Barry Finn provides very similar lyrics, which he found in a CD booklet from a recording by Skip Gorman. I'm not sure how Barry came up with James A. Bliss as songwriter and 1923 as the date of writing. I haven't been able to find any documentation of that.

This link will take you to background information on the song, and several recordings:

http://compvid101.blogspot.com/2009/05/colorado-trail.html