Thanks again everyone!
We ended up driving I-15 to 210 W to I-5 North. Traffic was super light, wow. And of course only 3 main roads to keep in mind. Now we're back home in San Francisco. I-5 N to 580 W to 80 W
Granted there would have been a lot of fun side trips to do on the drive, but this time we only wanted/needed to get to SF; but hopefully we'll have side trips (and a more spread out trip) for the futures!
Michael