Actually I don't know why this wouldn't work on a canoe trip, too.  Seems to me the box would fold flat easily and the whole setup would weigh very little and take up almost no room in the pack.  All you have to do is make sure the cardboard never gets soaked.  The oven bag top is a great idea too!

I may well try this one out on my next trip.  This might be just the thing to get me back into baking on my trips, something I have given up due to the weight and ineffectiveness of many of the oven options out there.  It's still kinda time-consuming (baking or fishing is a no-brainer choice for me) but it seems this idea conquers most of my other reasons to forego baking the past few years.