The water temps haven't dropped as much so it will be hard to judge where the fish are in relation to spawn in April. You might have to wait a bit to determine patterns. Three really easy things I have my kids do are a carolina rigged fish doctor, the Eakins jig, or a jig with a grub tail. They can always drag or hop them from the back of the boat and should snag something. Sometimes a spectacular tree or rock!
Where are you from in Iowa? I should be up there April 6-10 for work and am thinking of fishing Saylorville Lake.