Since this reply is 8 days after your post, you may already be there but here goes.
I recommend that you take I-15 and Hwy 58 to Edwards AFB for the first leg of your trip. Then through Mojave and Tehachapi and through Bakersfield. The route through the mountains around Tehachapi is pretty good. Then continue north on I-5 to exit 485 and take Hwy 12 over to Fairfield and Travis. This second leg is 385 miles so you might want to stop somewhere in between.
