Many Americans get to visit California by driving here. A number of interstate highways run into the state from points east and north. From the Pacific Northwest, I-5 runs north and south through the state and will get you here quickly.
The coastal routes along Highway 1 and Highway 101 are longer, but prettier. I-10 and I-15 allow access from the southeastern regions.
Most major car rental companies are located in one central area at the major airports. To reserve a car in advance, contact Budget Rent A Car (800/527-0700), Dollar Rent A Car (866/434-2226), Enterprise (www.enterprise.com [1]), or Hertz (www.hertz.com [2]).
Links:
[1] http://www.enterprise.com
[2] http://www.hertz.com