What are the 18 YO's into? If they're looking for the traditional hip California beach scene, then opt for Santa Monica to San Diego. The coast north of LA is more about scenery than shopping or laying out on a beach.
Currently, a good deal of the scenic stretch of coastline through Big Sur is closed due to rock/mud slides and a bridge collapse, so that might help with making your decision.
What Elle said! Drive through Malibu on PCH, it's beautiful. If you want to do things there along the way, here are some ideas:
For more information on the coastal route between Santa Monica and San Francisco, please go up a level to the California forum and read their top questions (full version, right side of the forum page). There is a lot of information on this very popular drive on that California forum, some pertinent to road closures after our extradordinarily wet winter.Edited: 01 June 2017, 12:11
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