If you have any doubt about the water ahead, get ashore and scout it on foot. Bring a length of rope. If a section is too challenging , you can walk the canoe down the side of the river.
I don't know what type of river you'll be paddling, but watch for low hanging trees, especially where currents on a curve will draw you into them. They're called sweepers, and they're most likely the number one takers of gear and givers of wetness! Bring a spare paddle and attach a leash to it. The currents on bends can be deceptively strong.
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Charlie