GMR is one of the best cycling roads in Southern California. (It's the road shown in my avatar.) Just keep pedaling, and you'll make it to the top eventually. It's a loooong climb, but is incredibly scenic and interesting. Note the the first little crest that you come to is not the top.

Right now it's closed because of the storms we had awhile back, and I don't know if it's even passible. Usually, they let cyclists use it even if it's closed but things may be different now with the extent of the damage done from all that rain.

If you do ride it, please report back on the condition.