Middle Fork State Fish and Wildlife Area is a lightly trafficked trail located near Collison, IL and features a river. The trail is good for all skill levels offers a number of activity options. Dogs are also able to use this trail but must be kept on leash.
dogs on leash
As far as the regular camping area goes, and the terrain, it's nothing spectacular. You share the trails with horses, but everyone is generally very friendly. The terrain change is pretty good for Illinois. Very close to Kickapoo State Park, which has canoeing and other activities. The great part about this park is that if you camp in the hike-in area, you will almost certainly be completely secluded (aside from a healthy, boisterous frog population), next to a pond. It's a nice, peaceful base camp, well away from other campers.