I used 2 harbor freight car dollies which are on sale often. They each have 4 steel castors. They are cupped to fit a tire, but I bolted 5/4 planks across them and connected 2 of the dollies with an appropriate length 2x4 on the end of the dollies. Then I laid a 24" or so 4x4 on top of each dolly to match where the skids on the rototiller hit the dolly. Looking back, you could forgo the planks and just use a 4x4. The 4x4 adds enough height so the tiller blades rotate freely when the pto shaft turns. This makes hooking up the tractor pto a breeze, well, maybe not a breeze. PTO shafts are always a pain, but when the equipment end spins easily, it makes hook up easier. Finally, I don't like using furniture dollies for something this heavy because the HF ones I have with rubberish wheels will develop flat spots quickly and don't turn when there is a lot of weight on them which makes them hard to move. Having implements that move makes hooking up far, far easier. The only downside is you need a concrete floor.