"Down the Trail to San Antone" was apparently introduced by the songwriter, Deuce Spriggins, in the film "That Texas Jamboree", 1946, and then sung by Gene Autry with the Cass County Boys in the film "Trail to San Antone", 1947. It has also been recorded by the Sons of the Pioneers, Riders in the Sky, and others.

I pieced the lyrics together from various sound samples found on the Internet. I don't know if these lyrics are complete, but it sounds as if they could be.

Note: Riders in the Sky introduce this with the spoken line, "Any mail, Ranger Doug?"

I've just received a letter from my girl in San Antone
That said that she would be my bride.
I know she really loves me and her heart is true,
So I guess I'd better take a ride.
I'll hop up on my pony and I'll ride away
Down the trail to San Antone.
I can see her standin' waitin' by that garden gate,
And she waits for me alone.
Through the hills and o'er the plains we'll ride, ride, ride.
I won't rest until I have her by my side.
Roll on, little pony. Let that ol' wind moan.
I'm headin' back to San Antonio,
Down the trail to San Antone.

Maybe someone else can supply the chords.