Decide where you want to live, do some research on towns which have regional & legacy bases.
As an O6, the currency standards may be lower for you than other mil pilots at least that's the latest rumor. Don't worry about flow to AA, you'll get hired off the street long before you flow. You're one of the few who will likely have his pick of legacy. In fact if AA is going to work best for you long-term then you may want to avoid AA-owned regionals because I think the flow will prevent you from getting hired at AA early. May need to research that.
Off the top of my head, these western towns have both regional and major domiciles...
SLC
DEN
DFW
IAH
SEA
PDX
ANC
SFO
LAX
PHX
I may have forgot something.