I would avoid Pasadena too. Not that there's anything wrong with the 210, but that's just not the right route.
The 58 from Barstow to Bakersfield is a great road now. Actually, it's the Barstow to Mojave leg that is great now, because that's the part that they widened and improved. From Mojave over Tehachapi to Bakersfield is good too though.
Once you get to Bako, you can pick your favorite route over to I5. The 46 is a pretty good road.
That whole drive should be pretty easy. Tehachapi is the only pass you'll go over, and it isn't bad at all.
Hopefully you're not in it for the scenery though, because most of that route is pretty bland.
