You have two VERY DIFFERENT routes there. PCH/US101 is the slower, coastal scenic route—–think Big sur, Santa Barbara and Monterey. I-5 is 3 or 4 hours faster——-but as dismal a ride as you can get. Think exists every 10 miles with no city in sight. My suggestion would be to take US101/PCH 1——-it’s an awesome drive and well worth the extra time.
Now, some details——if you can tell me something about where in L. A. you’ll be as well as which route you’re taking I can offer some great places to stop!