Upstream of Columbus-Fall River Road: The Crawfish splits into two branches upstream of the bridge. Both branches are very scenic and have some rocky sections that I've scouted extensively before. Unfortunately, logjams are a major problem this far upstream and I'm not sure there are many if any viable legs in this stretch.
Columbus-Fall River Road to Old Hwy 73: 3.8 miles. A mostly wooded section with perhaps 4 logjams.
Old Hwy 73 to Udey Dam/Columbus: 3.2 miles. Mostly slow flowage paddling. Somewhat of an urban paddle that goes through the northern outskirts of Columbus. Area parks are alternate access options.
Udey Dam to Columbus Wastewater Plant: 0.8 miles. An attractive fast section. Rapids and rocks will be visible at low flow rates. As of Sep 2019, there were two logjams, but they can be hopped over.
Wastewater Plant to River Road (Creek Bridge): 2.9 miles. A mediocre section with one logjam to sneak around. Current slows and the banks consist of a mix of woods and open sections.
River Road to Ninabuck Road: 3.2 miles. Terrific section with good current, healthy woods, light riffles and small boulders. This would be a very scenic section at low water levels.
Ninabuck Road to Astico Park (West Landing): 1.0 miles. Mostly uninteresting flowage paddling.
Astico Park (West Landing) to Astico Park (East Landing): 1.1 miles. A nice hilly section by Astico Park. Current is almost nonexistent though.
Astico Park (East Landing) to Danville Dam (Elba Street): 0.5 miles. A half mile of paddling a very silted-in flowage. The dam can be easily portaged along the eastern bank. Take out southwest of the dam. The mill here is very scenic.
Note: While local fishermen regularly use the shoreline south of the dam, it is private property. The owner is very nice about letting people use the shoreline to access the water. But be considerate if you take out here. If you want a more public access option, you could take out at Hwy T just downstream.
Hwy T to County Road TT: 5.1 miles. Artificially straightened by farmers, I suspect this might be an uninteresting segment.
County Road TT to Austin Road: 3.1 miles. Likely wide, slow and muddy.
Austin Road to Hwy I: 3.0 miles. Likely a mediocre section.
Hwy I to Hwy BB: 4.8 miles. A mediocre section that features the mouth of the Maunesha River.
Hwy BB to Hwy G: 2.3 miles.
Hwy G to Hubbleton: 4.3 miles. The Beaver Dam River adds considerable volume to the Crawfish.
Hubbleton to Olson Road: 1.3 miles. Wide, slow, muddy and likely boring.
Olson Road to Hwy A: 7.7 miles. Likely an uninteresting section.
Note: I'm not sure if Hwy A is a viable access.
Hwy A to Aztalan State Park: 3.1 miles. Likely a boring paddle. The highlight is Aztalan State Park.