if you stay on paved roads that are better traveled winter driving should be fine... no different then in northern wisconsin... better because there is less snow. No trees so the wind will play more a factor.. it will blow snow off certain roads and make big drifts on others. You just have to learn which roads drift and which don't as you go.
Overall temps are going to be warmer probably most of the time in the spring, summer, and fall.. though on occasion it will get warmer in Northern WI , especially in the spring, due to the way the jet stream brings warm air up into WI. It won't be a huge difference from what you have now when you average it all out, especially winter temps. Spring, summer, and fall temps should be warmer. You'll make the transition just fine... the weather is very similar.
One major difference is around the Yankton area, the thunderstorms start to get quite a bit more powerful then say areas to the north like where I am. I'd consider that a good thing because I like to watch them and get disappointed here. (Moody County, SD) Needless to say if you like to watch severe storms, they get quite ripe down there and you can see them from very far away.
You're kind of on the border there... the supercells really like to fire getting into Nebraska. Statistically, you'll see many more tornadoes there then you will in Northern WI for sure, but I wouldn't worry about that too much unless you plan to live in a few of those bullseye counties down in east central Nebraska.
http://www.hprcc.unl.edu/nebraska/nebraska-tornadoes-1950-2004final.jpg (broken link)