Your ultimate destination is TUS.

All routes to TUS are:

TUS-PHX, mainline. But, PHX is all TED, except the daily PHX-IAD

TUS-SFO, regional jet

TUS-LAX, regional jet

TUS-DEN, regional jet

Personally, I'd take the TED rather than the UX regional jet. What's so bad with TED? Unless you're on a first class ticket, TED is no different from mainline.

Same snacks, same BOB, same seats. The only difference is that TED doesn't give you the whole can of soda.