The problem with a sled is you will find areas where a home owner has cleared the sidewalk in front of their house right down to pavement and others that haven't so anything that needs to slide on the snow will have problems. I am also not a fan of crossing a street with a sled since a car sees the walking adult but might forget to wait for what they are pulling.

A wagon with wide wheels will slide along on most sidewalks and solves the bare patch times. It also keeps the kids up out of the slush and makes sure that hands can't get out of the sled, etc. Of course the expensive route is the runabout stroller which many swear by.

Is there the option of arranging with another mom going to the bus stop to get your son off the bus at least and then you arrange to pick up from them.