So how much wood are we talking on an annual basis? If you could stack it on racks and safely haul it over most average terrains, and get it out in 2 or 3 trips (in other words not a lot of wood), then I can see why you're going down this route. However, if you're talking about a cord per year, that's a noticeable portion of your winter heat and it really is worth putting some effort into. Instead of trying to find some really cool mod or toy that MIGHT help you get the wood out, how about you spend time and just fix the trail? Yeah, it might be a lot of work, but it will pay off in the first year. If you're trying to transport that much firewood over that kind of distance, do what you need to in order to make the trail safe. Otherwise you're going to be trying some rigged up solution and if it doesn't work quite the way you thought, you'll destroy your machine if you're lucky, end up in the hospital or morgue if your not.
Forget the log arch. Great if you are wanting to make lumber, but trailers are a lot more useful for firewood (my opinion of course). Buy/build a single axle trailer. Walking trailers are nice for really rough terrain, but if you'll fix your trail, you shouldn't need to spend the extra money. My terrain in southern Indiana isn't that bad because the trails have been fixed
When the ground is soft, I use the same 4x8 trailer to bring the firewood out that I use to haul the ATV down the highway. 4 to 5 trips = 1 cord. That may not work for you, but the point is that a trailer will bring out just as much firewood as an arch, and I use it for lots of other things too.
Adding a hitch isn't difficult but can take some time. I've got a 2003 Yamaha Big Bear, and the chincy sheet metal plate on it is pathetic. I built a full blow clevis hitch for it (think garden tractor implements) that also locked the rear suspension. It provided a nice solid location for a 2" receiver.