My favorite pack rifle is the Browning 22 auto, takes down small, and is a joy to shoot. If you want a very light rifle, the chipmunk is a small unit. Personally, I'm like you, my 629 6.5 inch 44 mag is a great river gun, shot for moccasins that want to join you, etc. Usually the Browning gets taken just for plinking etc. Another cheapie is the 75 dollar single shot from Wally World, saw it off to a legal limit, then cut the stock short too if you are a mind, and tie it with 550 cord to the boat, or take it apart and put it in a pack when it's not needed.