I just started using my 310-8 to haul firewood around my back yard this past summer, on a very occasional basis. I'm pulling a 17 cu. ft. cart full of hardwoods, so the loads are pretty heavy. But it's basically level grassy terrain, a distance of only about 50 yards or so each direction. The tractor handles it easily.
I don't have a great hitch setup on this yet, so I'm not pushing it too hard until I get something more appropriate. Right now, the cart has a square tube at the front. I just drilled holes through the top and bottom to accommodate a 3/8" or 7/16" hitch pin (can't remember right now), and it sits on top of the tractor drawbar. The pin is too long, so there's a good bit of vertical movement, which can't be good for the tractor, but it behaves pretty well if I take it easy. There's also some play between the pin and the hole in the drawbar, also not ideal. At the very least, I'll put some washers or a flanged bushing in there before my next haul to take up some of the slack.
And yes, I would feel much better installing a proper hitch for this thing, something like what Scott (smoreau) sells would probably work just fine. In time...
Here's a shot of probably the largest and heaviest load I've hauled so far. My semi-educated wild-arse guess is that the wood and the cart total maybe 800 pounds or so.