The problem was around mile marker 21, there is a tight curve with a logjam that forced us to portage through a farmers field on river right. There's a mud pile to get through of knee deep slop, then you go through a field, then slide down a ramp back into the river. A swarm of mosquitoes ate us while we portaged.
We continued on through downtown pecatonica. There's a sudo dam there, but if you stick to river right there's an easy channel to pass through so you don't have to portage. We'd continue on to the Pecatonica river forest preserve area where we found a shoreline to camp on.
53 miles took us 3 longer days of 6-8 hours of hard paddling per day. We slacked off a little, but they were longer days. The heat bugs and mud made this a tough river. Tough to paddle, tough to camp on. Maybe it's different in fall/spring, but I do not advise doing it in the summer.