Buy a Jon boat and motor, get a ATV and take the ATV across the water on the boat. Thats what the guys do at our camp.
Ive had five Argos's over the years and still have an 8 wheeler, as much as I love them machines, most everything in this thread about them is true. You had better be a good mechanic, know how to fix flat tires, and put them back on the rim, carry lots of rope to help winch yourself out when you get stuck, and a chainsaw to cut trees that fall across your route. Ive never broke down yet where I couldn't fix it to get out, but have come close a few times. Broken axles, flat tires, replacing the roll pins in the axles shafts happen when you start pushing them in the bush. I have been stuck in waist deep water in a swamp in mid November replacing the roll pins in the front axle, which is a job for a contortionist to reach. The firewall, engine ducts, and clutch have to be removed to be able to see the front axle buried in the machine. There is a learning curve in driving them, you will get good at reading the terrain on where you can or can't go, or be prepared to do some winching. Once they get sucked into the mud they can be almost impossible to move.
They are like a big bobber on water and you need a outboard to be able to maneuver on even the slightest current. I take mine about three km up river every year, and when the water is rough its an ordeal to get through, bilge pumps (plural) are a must as sometimes they take on water, especially on the rough days.
The new machines are better, and they have addressed a lot of the common problems, but they are now a very expensive machine to buy, 40k for one properly outfitted is not hard to reach.