We're planning to go but we're close enough to just day-trip it. (2 hours away).
If you find a reasonable hotel in Appleton, Oshkosh, or Fon Du Lac, the drive is less than an hour through some beautiful rolling countryside... a great way to start and finish the day.
You might look up some of the smaller towns and see what they have available. I'll bet most people only consider the bigger places.