If you were in my situation, what would you do?

I recently received a new "territory" (I use quotes because it's more a collection of states, instead of the NW or New England) that I'll be traveling to for at least the next year. My "territory" includes Colorado, Arizona, Tennessee, Arkansas, & Louisiana - so geographically, I'll be all over. A typical week might look like this: WAS-PHX-DEN-BNA-MSY-LIT-BTR-WAS. This being the case, I think that accumulating segments will be important.

I have status on a number of airlines, but wouldn't mind starting on AA/UA if those best served me (my company does have travel discounts with UA/US/AA/NW - I'd also get a status match on UA or sign up for the Plat Challenge on AA). I never want to get onto a US plane again, so I'm already crossing that option off. I am leaning towards using CO/DL but am not sure which program I'd consolidate my miles in. Nearly 100% of my travel are on full-Y fares because they're bought usually within 48 hours of departure.

So my question is this; if you were in my position, which airline would you want to use?

Thanks for all feedback!