I know the wheel horse blade that you are talking about, and the 184 tractor both very well. I think you have a good idea! The frame of the 184 is pleanty strong enough to handle what you want to do. I would try to find a point on the frame where you can bolt both up from the bottom and through the side of the frame, just to give some more support. Or, make a plate that bolts up under the frame, may be where you can get bolts about a foot apart (front to back) under the frame of the 184. Then make your mounting quick hitch down from the plate. Any way you go with it, if you spread out the load on the frame, it will hold up better and last longer. But, you're right, this isn't a difficult fab job, and the 54" blade is a good size for the 184. If you have the wide turf tires, you'll be plowing a narrower path than your tires, but that's not a big deal. Get us some pictures!!!!
Cub Cadets 682, 1811, 1864, Simplicity Legacy XL 4x4 Diesel with FEL, 60" mower, 50" Tiller