I've been twice...just the main building.
The 1st time, was on a whim, traveling from Kansas to Michigan. It was just me and my 5 year old(at the time)...not a good situation for taking time to look at stuff. Started well enough, but kids get whiney...AND heavy!
The second time, also on a whim, was on the way back to MI from a vacation in Tennessee...just me and the wife. Better than the 1st trip...but still....women!
Someday, the 3rd trip will be made solo!