There are three routes south from Monterey to LA/Anaheim, and they are almost equal in time.
1. 68E to Salinas, 101S to Paso Robles, 46E to Lost Hills, 5S to LA.
2. 68E to Salinas, 101S to LA. You can pick up 5S in downtown LA.
3. 1N to Castroville, 156E to Prunedale, 101N to San Juan Bautista, 156E past Hollister, 152E over Pacheco Pass to 5S.
The third route is longer in miles, but the higher speeds on the interstate make up for it.
When I actually lived in Monterey for 13 years, I always took the first route, though I had friends who swear by the third one. I now live in northern Monterey County, 25 miles north of the city of Monterey, and the Pacheco Pass route is a clear winner for me. But from town, I think it's 50-50. 101 is a little more scenic, though. But be sure to slow down a few miles before and after the speed trap / CHP office in King City.
You can shave a few minutes off the time by exiting 68 before Salinas, and going through the town of Spreckels. The road will go through a pretty tree-lined lane through town, then cut northeast to 101, bypassing the traffic of Salinas.
HTH,
Bob