The first 10-12 miles was fun: decent current and tons of eddies I could pick up to keep moving. I was paddling hard and scooting along, but never to the point where I burnt out. The river has lots of twists and runs through heavier forest, so it's scenic and fun.
Around mile marker 12/Lake Cook road, the river widens, and the current slows. This day, there was a major headwind, which really slowed me down. There are sections of the river that are wide open and have little coverage, so the wind can unimpededly blast you there. I was already starting to tire, and this wind really hurt. I had to paddle harder than the first 12, but to go slower than before. Factor in some soreness and I burnt out quickly.
The last 6 miles or so took a lot longer than the first 2/3rd. My strength waned, but eventually my arms went numb and I just pressed on with some divine support. I was thrilled to finish under 4 hours. The best paddlers and boats can do it in close to 2. It requires a thin cigarette style boat that can slide right through the water. The winners from my recreational kayak division made the run in about 3 hours.
I did grab video from the first 2 hours of the race. My gopro eventually ran out of battery, but this should be the first 10 miles or so. It formatted into 4 videos: