Unfortunately, your choice of location limits you to Santa Fe. The Rio Grande and Santa Fe were bitter rivals who fought drawn out court battles over territory, particularly the right to build over Raton Pass and through the Royal Gorge.
The only chance of anything other than Santa Fe running through northern New Mexico would be a natural calamity along the Southern Pacific's Sunset Route to the south or the Union Pacific's Transcontinental line to the north.
There were Boy Scout jamboree trains that ran during that time. I've seen pictures of them on the joint line headed south out of Denver. I don't know where they branched off after that. I suppose some heading to California or Arizona would have taken that route.
I disagree with cacole, all UP streamliners detouring to the south would have gone through the D&RGW Moffat Tunnel or through the Royal Gorge so they could meet back up with their normal trackage ASAP in Salt Lake City.
With the parade of AT&SF trains passing through where do you find in your schedule to fit in foreign stuff?