Sure, it would certainly be possible to include Death Valley on a route between Las Vegas and San Francisco. CA-190 goes through the National Park in an East-West direction. But you would then have to skirt around the southern end of the Sierra Nevada and that would up your driving time to closer to 11 hours. And that's still using I-5 up through the Central Valley. I just don't think you have the time to make this the kind of trip you want.

AZBuck