I-29 follows the Missouri...
I-29 follows the Missouri River and goes right through town. We are about 95 miles (90 minute drive) north of Omaha and 85 miles south of Sioux Falls. It is generally cheaper to fly into Omaha and drive up. However, there is a small airport in Sioux City. The airport code is SUX. No, I am not kidding.
You will need a car. We have a bus system but it stinks. And there are taxis but they are expensive.