John,
If you're going to try to miss most of the L.A. traffic conditions, may I suggest that instead of taking "The Grapevine" on I-5 and going through much of this traffic mess on the Foothill Freeway(I-210), that as you're going south on Hwy 99, and as you come into Bakersfield, that you take Hwy-58 southeast towards Barstow, and when you come to Hwy-395 take that south to Victorville, where it then connects to the I-15 south, and then when that splits off to the I-215 south at the Cajone Pass, take the I-215 south right into Riverside.
This might be quicker in the long run for ya. Traffic through Pasadena and points east towards Riverside from there can often be a bear, whereas the route I've suggested should pretty much steer you parallel and a bit north and away from this megalopolis's worse west/east traffic.
