Watertown is on I-29 about 4 hours from Minneapolis, 2 hours from Sioux Falls, 2 hours to Fargo/Morehead and 3 1/2 from Pierre and the Missouri River. Yes, you are 8 hours away from the Black Hills and winter fun but there are things to do East River as well. There is good fishing both summer and winter, bird hunting is extraordinary, white tail season is as good as you can find, you can snowmobile (if we get any snow), x-country ski, and there are jobs available. I've lived both West and East River and the people of South Dakota are uniformly friendly, if reserved at times (Northern Scandinavian or Germanic stock for the most part East River but that is changing all the time). No income tax although property taxes are a bit lower in the Eastern side.
Either way welcome to SD. I don't live in Watertown but have been there many times. Stop into the Terry Redlin museum if you like art based upon rural scenes.