Depends on Budget and Time Constraints
Tom,
If you have the budget and you're pressed for time, I'd fly to L.A., rent a car, and drive to S.F. You can take two days to drive up Highway 1 (the coastal route) and pass through some incredible towns and cities, as well as some of the best scenery in the entire country.
If you go ahead as planned, you're looking at about 1500-1600 miles between Houston and Los Angeles. I'd guess that Las Cruces, NM is about halfway between, but I'm too tired to look at a map right now.
Good luck and safe driving.
AB