The portion I used to drive was between Kettleman City (just of I-5) and Atascadero (off the 101). From Kettleman to a little crap hole called Cholame is pretty boring. But at Cholame, note the turn where 41 and 46 merge, that's where James Dean died. 5 miles or so down the road, make sure to take a left and stay on 41, cutting away from 46. This is where the fun starts. Take it slow through the other little crap town right there, but once you get through the town, take a left and continue on highway 41. This turns in to some of the best windy, hilly roads i've ever been on (about 15 miles worth). There are some blind crests and off camber turns, so be aware your first time out. At the end you'll find yourself in Atascadero.