We stayed for a long weekend at the end of June when the campground was almost completely full. The camp hosts were lovely! Since we did not have reservations ahead of time, we chose from the walk-in sites, which I believe are the first two loops closest to the entrance. Those sites, 5-46E, are very different from the rest of the campground. They're shaded by huge (by Illinois standards) pine trees and there is no privacy screen of vegetation between the sites, although they're nicely spaced out. The middle part of the campground has smaller trees and grassy lawns, still pretty open, while the outer loops are closely packed. With the outer loops, you won't have any cell signal, but you probably won't hear the trains, either.
The park: beautiful area with lots of interesting wildlife (quite a few snakes so be aware if that's not your thing) and great views of the river. I found the hiking trails to be significantly harder than advertised as they all start with a steep climb up the bluffs, but the views at the top were rewarding. Some viewing areas are accessible by car. There's not much to do in the surrounding towns, but this is a great stopping point if you're on a trip.
Site 11: electric with water nearby, close to the (very clean) pit toilets. Although there is a camp store and parking lot directly behind this site, the store was closed and looked like it was going to stay that way, so there was no additional noise. Being up front in the campground, you're closer to both the road and the train tracks, so be prepared for noise from that - but at least the AT&T cell signal was good! The tall pines were great for providing shade and still allowing a nice breeze, but you WILL get sap on everything.
The shower houses: the shower houses were some of the nicest we've encountered while camping - hot water immediately, hooks to hang your things, very clean, flush toilets and real mirrors. There are several shower houses throughout the campground.
A note about the pit toilets - the ones closest to the camp store (and I assume the rest, but did not verify) had the type of light that turns on VERY slowly, so if you're going at night definitely bring a flashlight! In addition, there was always some sort of critter in there - toad, fox snake, etc. I found it entertaining but my mother in law probably would have straight up died had she come along!