Military, retiring early 2018. For family reasons probably going to move to PDX area. Looking at DAL and UAL...I posted a similar question on the Delta board given their SEA domicile, but now I'm curious how painful the PDX commute would be to SFO if I were to get hired at UAL. Here are the main things I know and my main questions:

- There are a lot of daily flights between the two airports, but I've heard there are a lot of PDX commuters.. would this be a jumpseat nightmare?
- What do pilots mean when they talk about "commutable" lines?
- Sounds like SFO is trending less junior but do you foresee it remaining junior in the long run? A big reason I would consider a PDX-SFO commute is that my seniority would build quickly in SFO.
- I've heard LAX is more commutable but more senior. Should I be aiming to get to LAX instead of SFO?

Thank you in advance!