So much depends on what you and your 12yo like to do -- outdoors? educational like museums and historical sites - how people lived long ago? Riding the Seilbahn, ropeway, tramway - whatever - up Sandia (that's watermelon in English) ridge?
I tend to agree with those who say Albuquerque. If you stay 2 nights, take the day trip to Santa Fe and walk the young one up to Martyr's peak and down again to the famous square - the exercise will do you both good -- and make visiting the Palace of the Governor museum welcome - some real good history there.
Also there's a lot of youngish students (JHS thru CC) who commute on the Rail-Runner - I know my kids, when they were 12, really liked to see how "grown-up" teenagers behave (pretty good, usually!)
If only only one night layover in ABQ yo9u could see the Biopark (zoo, botanical gardens, aquarium) or try the Sandia Ridge tramway.
I took a 3-night layover in Albuquerque from the SWC this May - having a 12yo along might have made it even better.
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PS - some of the best times I spent with my (then) 12 year old kids was just walking and talking (or not) and seeing new things together.
Hope your trip is good.