My friend and I have canoed the entire 45 miles of the Salt Fork, 6 miles of the Big Vermilion, and 10 miles so far of the Middle Fork. The Middle Fork is designated as a National Scenic River, the only one so designated in IL. But both the Salt Fork and Middle Fork are beautiful, with towering shale cliffs, sandstone bluffs, wetland prairie, heavy timer, cool old steel truss bridges, TONS of fauna, great fishing, lots of fun and easy riffles and rapids, several sand and gravel bars for picknicking.
Public access is plentiful, with many access points on public land, or along township roads with adequate parking and (mostly) mud-free departures.
The Big Vermilion has one very dangerous lowhead dam that must be avoided, it is just past the downtown Danville area. There is a prominent warning sign 3000 ft upstream of the dam, where one must turn left up the North Fork to the Ellsworth Park takeout. Nonetheless a 12 year old girl was killed last year when she and her sister ignored the sign and the instructions given by the outfitter and went over the dam.