Seeing as the G-Trax lightweights had been repainted for the American Freedom Train, why not the Golden Spike Centennial Limited from 1969? It was run from New York to Salt Lake City to commemorate the 100th anniversary of completing the transcontinental railroad and was hauled by NKP #759 in special "American Railroad" livery on its tender, as well as a UP Centennial and then-UP 8444 as well as a specially painted GG1.
Details about the train and the consist can be found in this video. I think we could get a reasonably accurate consist using the freeware lightweights: