If you feel you need a plan B get it in place. Get the framework sorted. Have a destination and think ahead waiting for it to happen means its already too late as countless millions found out during the 19th and 20th century
With regards to the mid term I expect violence regardless of the result.
My wife isn't as worried as I am, but I am going to make sure we get our passports updated, just in case. That said, even if the US does slide off the deep end, my wife and I have a lot that'll protect us if things do go pear-shaped - we're 1) white 2) financially secure and 3) in Maryland, which is a rather liberal state. With the exception of the last one, we look just like Trumpies, so we can blend in.
My wife isn't leaving her tenured position (which I can't blame her for) unless it gets really, really bad, and I can't convince her to move elsewhere, even though I could likely get a job in multiple countries (the company I work for has studios across the world, so a transfer wouldn't be hard). But the the more I've thought about it, the more I'm convinced it's good that we're staying for now, even if the Republicans win. If we have this much privilege, I figure, we might as well use it, because there's a whole lot of people who *aren't* white, *aren't* wealthy, and can't escape the US if things get really bad. The least we can do is hang out and donate to candidates who will try to slow down the dismantling.
The reality is, Trump's worst policies are and will continue to target immigrants, anyone who's not white, and LGBT folks. That's not us, which makes me feel all the more guilty, honestly. White rich people (and brainwashed white poor people) are Trump's base, so he'll target them last or not at all, which means our lives aren't really going to change that much unless we move straight into Trump for life, and even then, we'd probably still blend until we escaped.
That said, I am 100% getting my daughter out of this country as soon as she's old enough to travel regardless of where the political system goes. I'd prefer to do it even earlier (always the chance of a school shooting, since that's just something we've decided to live with) but my plan now is to convince her how much fun it would be to study abroad (when she goes to college) and hope she meets a nice guy/gal wherever she goes, gets married, and ends up in a country that is not the US. If she goes somewhere that isn't run by racist shitbags who've decided we should let kids get shot in school so the NRA can make money and a bunch of gunnuts can shoot cans with AR-15s on the weekend, I will die happy.
But unless we can completely remove the GOP from power and make it again socially unacceptable to support shitty/hateful policies, I don't see the US ever improving. One thing we've proven by electing and then SUPPORTING someone as horrible and corrupt as Trump - the stupid in our country is entrenched, it's not going away for decades or longer, and the obscenely rich have already won.
EDIT: Skip is also right that we've always had these problems. Many of us (like me) just weren't aware of them due to our privilege.