Depends on where exactly you will be fishing.
Out by the State Park I have seen anglers pull smallmouth on nearly everything. It really depends on the depth you're fishing, clarity of water, temperature of water...etc..
Overall some good lures would include Rapala, Rebel Crawfish (nothing TOO BIG), mainly any assortment of crankbaits that range in a natural color of food for the smallmouth. The Kankakee River is filled with Crayfish, therefore a crayfish color is ideal when fishing.
Mepps Spinners as well as spinnerbaits have been working quite well already this year as well!
Once you find one smallie, you'll generally will come across more in that area.
Due to the heavey rain we had about 5 days ago
, the river has come up and clarity got worse but it's starting to look better therefore early next week (As long as no rain) the smallmouth action should be ideal, especialy with the consistant warm weather we have been having!