Techniques for getting over the Mountain.

Going uphill, if you develop any sort of "problem", adding power is not going to be helpful in any scenario I can think of. The trailer is not going to pass you going uphill, and adding power will probably only exacerbate whatever problem you're dealing with.

Going downhill is an entirely different matter and working at/below the mid RPM range is probably a better overall choice.

 

@STexan has it exactly right. If you are pulling a slippery grade there will rarely ever be a situation where you need to apply more power. The only caveat I can think of is the idiocy of mega carriers that govern max rpm in low range at about 1600 rpm's. That's well below the normal max horsepower at 2000 rpm's on most engines.

Climbing a slippery grade I never ever get my foot to the floor at any rpm. If I am feeling a need to do that, the correct thing to do is downshift and then stay easy on the throttle in the 1500-1700 rpm range.