Here are more California highways that don't terminate at other state highways:
Most of CA-146 is winding and only 1 to 1½ lanes wide, and it is split in half by the mountains in Pinnacles National Monument. I’ve had a chance to hike the trails between the two highway ends - one of them passes through caves that require a flashlight.
CA-162 has a 50 mile gap, with a dirt road connecting the 2 ends over Mendocino pass. In addition, the eastern end of the state highway stops abruptly in Brush Creek (the portion of the road eastward from here to Quincy used to be a state highway long ago).
CA-59 ends in Snelling and changes its designation to County Route J59. Tuolomne County wants J59 to be redesignated as a state highway up to CA-108/120, since it was recently improved.
CA-203 ends at Minaret Summit (it was originally proposed to extend westward through the Sierra Nevada mountains to provide access between the Central Valley and Mammoth Lakes).
CA-131 ends in Tiburon after only 4 miles.
CA-169 ends at the Yurok Indian Reservation.
CA-180 dead-ends inside Kings Canyon National Park.
CA-191 ends in Paradise.

CA-198 ends at the border of Sequoia National Park.
CA-202 ends at the California Correctional Institution at Tehachapi.

CA-211 ends in Ferndale (it was originally proposed to extend down the coast to CA-1).
CA-270 end just before Bodie State Historic Park (the road continues for 3 miles unpaved).