With My GMC, I put it in tow mode and 1st gear at the top, leave it there until the trans gets warm, let it go to 2nd for a brief time and cool the trans down, then back to 1st.
Works well for me, I do use the brakes when in 2nd, but never enough to get them hot enough to glaze over. I have an infrared thermometer and have checked the rotor temp after the hill, nothing scary.
I have seen pick ups not towing smoke there brakes on the hill, a little common sense goes a long way. If you go way back to the 70's, the road was not even paved all the way.