I would vote for going up over going down. Using low gear to avoid overheating brakes
going down is a must that one can avoid if you route your trip to be going up. No possibility of trailer push making control more difficult when going up.
If it is correct that speed limit is really low that is another argument for going up, you control you speed more easily going up where gas pedal determines speed than going down where you have to fight gravity to maintain a low speed.
That said I have done both on several mountain passes in Colo. and you won't get to do much looking at the scenery either way. Driving will demand your attention.