GSUFALC

Hi All! Looking for opinions on my minor predicament here.

I'm based in Houston and will begin traveling for work to Seattle, basically every other week for the next few months (likely 10-12 times, and probably more in the future). I moved from Atlanta a few years back so all of my status (currently silver) and miles are with Delta. I'm also currently building up for Companion Pass w/ Southwest, which I'll accrue through their two credit cards. I have a Delta amex as well.

Getting from Houston to Seattle and back, it looks like my best direct options are United (more flights) or Alaska. At first, I was thinking I'd just stick with Delta or SW and stomach the layovers, but I'm starting to think I will regret that! So will my girlfriend/social life, etc.. If I was planning to be in Houston long term, I'd just switch my allegiance to United, but I'll likely be moving back to Atlanta in a year or two. To all the road warriors out there, do you think it's worth it to stomach the layovers to build miles/status with your current airline(s)? Or temporarily move to what's convenient?

Also, if I make the switch to United, is it worth it to grab the UA Explorer card for bag checking, 2x mile accrual? I also need to re-up my TSA Pre, so it is enticing. That'd put me at 4 airlines cards which I'm not excited about, but I'd likely just cancel in a year or two once I move from Houston and start flying with Delta again.

Any help or thoughts is much appreciated!