Richard:
First of all, I would contact the D&RGW Historical Society in Denver, they would have all the necessary information.
I model Rio Grande myself, though not quite back that early--my era is largely 1939 to about 1952. But Rio Grande passenger equipment in the era you're interested in, was painted the standard Pullman Green with black roofs. The more famous "Grande Gold" and silver didn't come along until the late 'forties, early 'fifties and if I remember correctly, was first applied to the "Royal Gorge" and "Prospector" trains. There was a period during the mid to late forties where a four-stripe gold was applied to some Rio Grande standard diners,
Being a 'bridge' route for through east-west passenger service (along with Burlington and Western Pacific), Rio Grande's own passenger fleet was relegated mainly to head-end equipment, coaches and diners, with a few 'overnight' Pullmans. To my knowledge, the Pullmans in that era were lettered for the Pullman company itself, and not the railroad.
I would assume that the "Mountaineer", at least from photos I've seen of it, consisted of Rio Grande head-end cars, coaches and diner, with several Pullmans for through passengers either to or from Denver (that was a pretty long, circular trip).
But I'd definitely contact the D&RGW Historical Society, because if I'm wrong on any counts, I'd hate to mislead you.
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
I am searching for the paint and lettering schemes for D&RGW passenger cars, particularly for the Mountaineer that ran between Montrose and Denver, circa 1920.