Trinidad CO to Clayton NM (160->389->551->325->64)

It's all two-lane. Haven't driven that route recently so can't say what condition the roads are in these days. You can spot check them with Street View on Google Maps, but that won't catch small bad stretches unless you're lucky.

I used to live in Trinidad and did Raton pass all the time - just did it recently with a fifth wheel. You've got the Duramax and should have no issues with the pass.

Rob