You need a bike and enough will to wake up early. Reeeeallly early. But if you don't have a bike or you don't wake up early, it just doesn't work. Oh sure, you could come close, but you'd never reach the nirvana of climbing Conzelman Road (at your pace, no rush!) with a truly unique and stunning scenery.
I stole this picture from @alex_lod
And here is another one from Robert, taken this morning:
The light and scenery changes very very fast - At least, when and it's not foggy :) So you don't get an idea of how it's like until you do it.
Totally. worth. it.
(wake up at 5:30, meeting point at ~6:30 on the top of Arguello)