Do not pass this trip up. Depending upon the size of your group, some of the guys wouldn't have to stay on the Kohler property -- there's a Baymont Inn in Sheboygan which is clean and signficantly less expensive than the Inn at Woodlake. On the other hand, you don't have access to the spa (great cold plunge pool and steam rooms) if you're off property. The American Club is a wonderful hotel, but unless you have your wife or significant other along, not in my view worth the extra cash -- and it will be plenty.
The Horse and Plow is a great place for post-golf dinner with a group, but there is also the "5 Star" Immigrant Room if you want to hurt your credit card a little (the breakfast buffet in the Wisconsin Room is the way to start your day).
After the 1st four holes on the River Course, you'll be looking around wondering why everyone has been raving about the place, but hang on. . . the next nine holes are among Mr. Dye's best ever, anywhere. Start on the 5th tee and enjoy the ride. You'd better be hitting your irons well, though, because if you miss these greens, or even hit them in the wrong places, you're in a heap of trouble.