Drive up the coast along Highway 1 to Big Sur and Monterey
http://jrabold.net/bigsur/
Stop at Hearst Castle. It's a must see unique place.
http://www.hearstcastle.org/
The Monterey Bay Aquarium is great
http://www.montereybayaquarium.org/
17 Mile Drive is world famous
http://www.tripwiser.com/trip_thing_to_do-Seventeen_Mile_Drive_Carmel_California_USA?itiNodeId=402881e70d84ac46010d84e6202f111f&eType=activity
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It's not the coast but Sequoia National Park is worth the trip.
http://www.nps.gov/seki/index.htm
There are many trails that connect the Sequoia groves.
http://www.sequoia.national-park.com/hike.htm
Besides the Sequoias, there is a rare marble cave in the park (most caverns are limestone). Crystal Cave is accessed by a picturesque half-mile trail that leads to the Merced river valley.
http://www.sequoiahistory.org/cave/cave.htm
Moro Rock is a great hike. You climb nearly 400 stone steps to the top of the barren rock (6,725-foot elevation)
http://kevingong.com/Hiking/MoroRock.html
http://en.wikipedia.org/wiki/Moro_Rock
Enter the park from the south, CA Route 198. It doesn't allow RV's or trailers so there is less traffic. It's a mountain road that climbs thousands of feet, has great hairpin turns and the views are spectacular.
http://maps.google.com/maps?q=merced+map&ie=UTF8&split=0&gl=us&ei=CGyMSt3lMIiksgPG5oi4CQ&ll=36.486453,-118.875504&spn=0.422878,0.447693&z=11
There is lodging at Three Rivers, CA and it is close to the entrance.
http://maps.google.com/maps?sourceid=navclient&rlz=1T4HPIA_enUS314US314&um=1&ie=UTF-8&q=three+rivers+ca+lodging&fb=1&split=1&gl=us&view=text&ei=9m2MStz2LIWQsgP137S1CQ&sa=X&oi=local_group&ct=more-results&resnum=1
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Yosemite is one of the most unique places on earth. It's one of those places you must see before you die.
http://www.nps.gov/Yose/index.htm
If you want stunning vistas, Yosemite is the place. Glacier Point is breathtaking.
http://www.yosemitefun.com/glacier_point.htm
If you want to see big trees, there are groves of Giant Sequoias in Yosemite (they are the largest trees on earth, bigger then the redwoods)
http://jrabold.net/yosemite/intro4seq.htm
After you visit the Yosemite valley and Glacier Point, if you have the time, drive across the park on CA 120. It takes you to the east entrance to Lee Vining near Mono Lake. The lake is in a caldera of an extinct volcano. CA 120 crosses Tioga Pass, the highest vehicle pass in CA. You climb thousands of feet on a mountain road and reach the Alpine meadows of Yosemite.
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=mono+lake&sll=37.88786,-119.281311&sspn=1.604034,1.790771&gl=us&ie=UTF8&ll=37.956109,-119.215393&spn=0.774205,0.895386&z
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Here is a list of California Scenic Drives
http://www.milebymile.com/main/United_States/California/region_byways.html