This gear would be intended for semi-wilderness day trips. The "worst-case" scenario would be a dislocated shoulder or broken bone in a remote area. I always paddle with a group, and in rapids up to class IV (for now). In those conditions, it is extremely likely my friends would be able to retrieve my boat and gear. In that situation, my plan is to have one person stay with the injured person while the rest of the group paddles out to get help.

I'm not concerned about water temps, since I'll be dressed appropriately for a potential swim. I'm more worried about a sub-freezing night.

I will listen to all the advice, and get the essentials into a pocket - probably a heatsheets bivy bag, a firestarting kit, a few water purification tabs, a pin kit (for retrieving stuck boats) and a bit of food - in addition to my current knife, throw rope, and basic first aid.