Pulling Travel Trailer in Colorado with Tahoe

Not exactly the same as what you are asking, but I towed a 7000 pound boat with a Yukon Denali XL. The biggest problem I had was both transmission and engine temps. The final nail in its coffin was after I added a larger aux transmission cooler which had the effect of blocking too much of the radiator. The tranny would stay cool, but the engine got hot enough to shut off air conditioning and reduce power going up Mount Vernon Canyon, just outside of Denver.

So, my moral of the story is to be cautious how big of a trans cooler you get. Your engine will sufficiently pull your weight through Colorado, but temps will be your enemy.