Thank you all greatly for your replies. I have taken all of them seriously, done more web research and pondering.
While pondering, I remembered I have a practice, when sleeping outdoors where it is cold at night, of putting my next day's clothing inside the sleeping bag and dressing inside the sleeping bag before getting out of the bag. This provides clothes that, if not warm, are not the ambient outdoor or tent temperature. This practice calls for a larger bag and limits me to a bag and not to a quilt. I'll try the Wiggy.
These days, I also carry a very lightweight hammock for those times when there is literally no place to put a tent that is dry and reasonably level. That said, I can't rely on hammocks because sometimes there are no trees from which to hang them.
Many years ago, I did three long trips on a rivers in Quebec for which there was no map, no guide, no records of descents. Not saying no one had done it. There were very old portage trails found. Only had topo maps. Under these conditions, one never knows what is downstream and where one might be able to camp.
Regarding capsizes: I remembered a capsize on a day trip on the Illinois River when I was in girl scouts. I probably was 13? and did not know much. It was early spring and the water was very cold. Our canoe got too close to another canoe in our group and my canoe capsized. I am not sure how, I knew so little then.
But, the experience has colored my interest in level of safety. The shock of hitting the cold water literally took my breath away. Thank god I was wearing a life jacket. I got to the shore easily enough, but after that was huddled and freezing cold on the bank side. Another girl in our group, a bit older, went off and found a farmhouse where we could get warm and were given hot chocolate.
Again, I thank you all for your experiences. I appreciate it all.
Erica