Alaska is truly the best for intra-west coast travel. I'm at their lowest elite level and my upgrade percentage is almost 100%. The only problem would be traveling from SF Bay to SoCal. There really is very little service save OAK-SNA. You can use AA for those routes (and earn status miles) but you might be better off with AA if most of your west coast travel is within CA.

Also, note that CO miles do NOT count toward status on AS:

http://www.alaskaair.com/mileageplan...rs_Airline.asp

AA, NW, KLM, QX (Horizon), and Lan Chile earn status miles.

Also keep in mind that AS elites get a few upgrades on NW but you are at the very bottom of the upgrade list. I'm currently one for four in the last year.