I’d like to someday have a bike+canoe setup and do some island hopping around Vancouver Island. My idea is to go fully human powered over both land and sea. Wicycle.com sells ultra-compact trailers that can pull a canoe or kayak of any size. Here’s an example of an Old Town canoe being pulled along by mountain bike.
Then once it’s time for a water crossing, you can break the bike down and pack it into the canoe. One Old Town canoe is big enough for 2 bikes plus some cargo.