At Monarch Pass, you need to work at keeping it a slow ride down, as it is easy on some of the straight sections to get up over the safe speeds for the curves.
With my C motorhome, 13,000 pounds and Ford V-10, I had no difficulty maintaining the (reduced) speed limit on the climb. I even had sufficient power reserve on the climb to accelerate back up to the car traffic speed after getting slowed down behind large trucks that were climbing at 15-30 mph.
US-50 is not like the Interstate. There is nobody climbing at 70-80 mph, everybody is down to 45-55, the curves demand that you don't get too far over the speed limit.