The Kenosha Public Museum is the strongest all-purpose stop on the harbourfront. Its natural-history galleries include mammoth skeletons and Ice Age material from southeastern Wisconsin, while the upper floor mixes regional art, taxidermy, and rotating exhibitions.
It is not a huge museum, but it is well pitched for travellers: free entry, lake views nearby, and enough substance to justify an hour or two. Pair it with the Civil War Museum next door and a ride on the streetcar loop.