I have ridden many of the bike trails in Wisconsin. Most are crushed limestone trails and are well groomed and in good shape. That being said, a 700x23 tire on a typical road bike will not make the ride enjoyable IMO. It can be done, and I have done it for short lengths. Last time on my road bike I bailed after 6 miles on the crushed limestone path because I was more focused with staying upright and finding a clean line than I was enjoying the ride.
28 tires may be the minimum for an enjoyable ride. Also reduce the tire pressure.