I've had tractor-mounted snowblowers for more than 20 years. I clear 8 places, 5 with gravel roads/drives. At the beginning of each season there are always a few loose rocks that find their way to the surface. The vast majority just go through the blower with the snow. Now and then something causes a shear bolt to break - maybe happens once or twice in a season - sometimes not at all. Up here the ground freezes which helps a lot. If your Virginia road stays loose, skid shoes will help as will a pipe on the plow edge.
It is true that heavy duty blowers are made stronger and handle rocks better, but they are hard to justify for locations that don't get big annual snowfall. On lighter units, changing out shear bolts is simple and quick.