Being from Tomball/Houston, you know how varied freeway traffic can be.
Last year we traveled (towing 34' fifth-wheel) from Colorado Springs on the way to Glacier National Park. We drove through Colorado Springs (we were camped on the Southern edge), Denver, and Cheyenne without a problem, just normal city driving, no significant delays. This was in the morning, rush hour in Colorado Springs, just after in Denver. Maybe we were just lucky, but that was our experience. I would not hesitate to take I-25 again. Not telling anyone else what to do.
BTW, my wife is a native of Magnolia.
Let me know if I can be of any help on the route to Colorado. We make it a couple of times a year. Will be leaving at the end of next week for Gunnison/Crested Butte.
We usually take US 287 out of Rawlins, WY to go up to Tetons and Yellowstone.