They are not the most ideal "watercraft" for duck hunting. A little awkward and kind of slow getting around. However, if your walking back a mile it might be the best option for mobility. Based on that Id get the float tube. Strap it to your back and go.
Ive seen a fair share of these things at yard sales for very cheap. Might be something you could pick up used and just hide it in the grass.
Heres on for 15 in madison
but as a way to cross a patch of water to get to a dry spot...could work great as long as the water stays below the top of your waders while sitting in it and you get the flippers over your waders.
Personally, I'd consider purchasing a small boat, especially if you could drag or cart it back to where you want to hunt, but I'm not 18 anymore.
Do your research and I hope you enjoy your hunt however you decide to do it.