Headed West.

So, next year (April maybe), I'd like to take a trip out west. One place I will be stopping is Grand Canyon. I've also been thinking of making the quick trip to Cali. I'd love to shoot some beach/rocks/cliff/suns​et style stuff there. What areas of the Cali coastline should I hit up?

GC is awesome, you going South rim or North rim? South has most of the popular shots you often see as well as some great visitor centers. If you are making the trip from the East I also suggest stopping at Antelope Slot Canyon in Utah, it's not too far from the GC and well worth the visit as the photo ops are out of this world.

As for the CA coast, the epic spots are along the Coast Highway from Moro Bay north to the boarder, that is where all the cliffs and spectacular views are. A good central spot is Monterey Bay area as you can hit Big Sur and 17 Mile Drive near Pebble Beach, or go north to San Francisco. If you want the long sandy beaches then go south to areas like Huntington Beach, Laguna Beach which have some beautiful (warmer) beaches.

Hope that helps.

+1 on the GC being awesome, and April is a good time (not too hot yet, and the tourists have not yet begun to get thick.. The only negative about April is that it may not have any clouds going on (depends on the year).
The South Rim is where everyone starts out, but if you're looking for something different from the "norm", the North Rim isn't a bad choice (either way, make your reservations NOW if you plan to stay overnight in the Park, especially on weekends). Of course, Arizona also has Antelope Canyon, Monument Valley and a host of lesser-known sites to chose from.

In CA, the coast highway from LA north (it starts to get interesting after Santa Barbara, though Malibu has some excellent people-watching opportunities) is definitely worth driving. Once you pass Point Conception, the coast gets a lot wilder and rugged, and, as T2i4me said, once you pass Morro Bay or San Louis Obispo , it's great - that's where all those car commercials of the "winding seacoast road" are taken . You can also check out San Simeon for some "civilized" stuff, and don't think about passing Point Sur without getting out and hiking around. North of Point Sur, the coast gets a bit less wild, though the points are interesting, and places like Monterrey, Santa Cruz and Pillar Point Harbor are also attractive.

North of San Francisco, Point Reyes is a must, though this entire coast is much more prone to rain and fog (and cold, wet wind) than further south.

South of LA, the coast is a LOT more "civilized" and with more beaches - the iconic bluffs overlooking the beach at Torrey Pines is one of the better-known parts. Take the ferry from Long Beach out to Catalina for some excellent (and rugged) seacoast viewing.

Hope this helps!

North Rim GC usually doesn't open until some time in May.

We were at north rim the first week of June.....still snow on the ground under the trees.

When we were in southern California last year we loved the Channel Islands and Joshua Tree National Parks. We were on Santa Cruz and while it isn't really beachy, it's beautiful.

I was going to suggest Point Reyes as a previous poster did. However, what I liked about it was the fog and mist. Very atmospheric.
You ask a very large question as there is so much to see in the west it would be helpful to know your exact itinerary...for example, if you are driving from the east, there are dozens of spots along the way to stop that are almost the equal of the Grand Canyon. I was just out in southwestern CO and had a very difficult time narrowing down what to visit. Spectacular places all.

I'd be headed out from Austin. So far the only thing I've put on my list as a must see is the Grand Canyon.

One thing to be aware of is the weather. I went on vacation in April and it went from great on the first day at Monument Valley to wind. dust storms and snow at the last stop at Grand Canyon. Here s the only sorta acceptable shot of the south rim.