Drove that with a loaded Ford Expedition V8,gas, pulling 4500 lb trailer both east and west. There are slow traffic lane pullouts often enough that you should not feel the need to strain your rig. Can't speak to your preferences but I was able to maintain 35-45 uphill without noticing a lot of engine/transmission groan. With the slow lane opportunities you should be fine. It's a very scenic route in many places and worth it. My best argument for that route is:....................At least it's not I-70 across Colorado! I-70 from Denver to Rifle is Awful.
Greg