Many of the responses seem to assume that there is a "right" version of this song (and, of course, it happens to be the one the responder knows). Cowboy songs, like all ballads, were transmitted orally, with changes that came from mishearing, misremembering and deliberately modifying the version heard. It may very well be "I ride an old paint," but it might have been "I'm ride'n Old Paint," and it is likely that it was "I'm leading old Dan." This makes sense, and "I lead an old dan" does not. I prefer "I'm" in all three clauses (including "I'm goin' to Montana") because the parallelism makes the best sense. The explanation that "hoolihan" was roping technique is backed up by authorities on cowboy jargon. If one doesn't know that, one might think that it refers to going on a "bender"--but that would be a reason to go to a city, not a state. ("Hooligan," which has nothing to do with this discussion, didn't come from Russia, but was borrowed into Russian from English according to the "Barnhart Dictionary of Etymology," but it is said to be of unknown origin by Hoad. I like the idea that "fiery" and "snuffy" refer to the emotional state of the cattle. Again, it makes sense out of nonsense. We expect even the language of Shakespeare's plays to make sense, and scholars do assume that errors were made by transcribers and editors, and they do change the text.