As another commenter pointed out, it is not so much a southern divide as it is a metro/rural divide. You'll find just as much Trumpish thinking in Montana, central Illinois, Wyoming, Idaho, and the Dakotas, as you will in the South.
The problem is that the rural areas of this country are disintegrating on almost every level. Their schools are awful, many of their communities are steeped in drug (meth and opioids) and alcohol abuse, family violence, and despair. Much of that is fueled by the collapse of the family farm, and the rest is because there are no jobs.
Most of these people want to work with their hands. They don't want to get some crappy job in an Amazon warehouse.
Create a new jobs plan. WPA 2.0. That guy who loves carpentry? Let the feds pay him to spruce up his decaying town. Get all the craftswomen and men working to rebuild their communities. Pay them to do what they love to do. Get some 3D printers into their hands. There should be no limit to what the feds can do to reinvigorate their economies, but we lack the initiative and imagination to think our way out of this problem.
At a bare minimum, educate them. Get them smarter. Stop throwing the men in jail on meth charges and get them rehabbed. As long as Democrats keep refusing to think out of the box, the problems will continue. A WPA 2.0 would go a long way to fixing things, along with a genuine commitment to education.
This would help areas with urban blight, too. The Black community turns to Democrats because it's the only party that isn't overtly racist of the two. But Dems haven't really done squat for them, either.
It's time to roll back Reaganism once and for all. And start thinking New Deal at almost every level we can. We have the money. Well, some of us do. Time for a little old fashioned redistribution of wealth. Time to end this 40 year Ayn Rand reign of terror.