You do not have to take off the impeller & auger. You just have to "split" the tractor half from the bucket (or scoop).
You do need a way to hold up the handle bars so they don't fall to the floor. 4 bolts.

I don't remember splitting these to do belts. With the cover off, you should see if there is room between the pulleys. If you put your model in Toro's parts look up, then look under the manual tab - there should be a free service manual.