From Costa Mesa, I would suggest going north on the 405 then merge north on the 605. the 605 dead ends into the 210, go west on the 210, and finally north on I-5. That will drop you just north of the I-5/405 merge and south of the 14 split. For a bit of peace of mind, you might want to take the truck route(as the normal car lanes get boogered at the 14 split till you get over the hill top).
It has recently started taking 3 hours from Mojave to Costa Mesa going that way in the morning during "rush hour" in a loaded semi.
55 north to 91 west to 57 north to 210 west is okay, but the am traffic on the 91 can be bad. And the 57 traffic from noon and on can be bad too at the 57/60 interchange. If you do take the 57 route, make sure to stay in the right 2 lanes as the 60 comes in from the left and leaves from the left. A lot of slow truck traffic as that is the start of a grade going east on the 60.
If you choose the 605 route, just stay in the 3rd lane from the left(not counting the car pool lane) and you wont have to switch lanes till the 210 if you decide not to.
On the 210, at the 134/210 split, be careful, almost any time of the day you go through there, it will be slow. The 134 goes straight and the 210 veers to the right.
As other have said, avoid I-5, 405, 710, and 110(nothing like taking 3 hours to travel 54 miles

)